I have had a few different cams over the years, different brands and different styles.. in different cars.
Currently in my Crosstrek I've got the BlackVue DR590-2CH and in my wife's Mazda I (still need to finish installing) a BlackVue DR490L-2CH (with a screen).
Initially I had mine mounted on the mirror stem with a generic version of the BlendMount (something like this
https://www.amazon.com/Dash-Cam-Mirror-Mount-Cylindrical/dp/B07H1LH4NL)
Same with my wife's.
I found that, to my own like/dislike, the front window visibility of that mount made the camera stick out too much.. like, really 'in your face' there's a dash cam there. I ended up moving it off that mount and sticking it to the window behind the mirror somewhat off to the passenger side a little.
No (known) issues so far with the EyeSight.
I also use the Power Magic Pro in the Crosstrek for battery protection. I have not had any issues (in any cars) with battery drain. Although when I go to the airport for parking on a week vacation I do disconnect the camera, not necessarily for the battery drain but for theft deterrence. I can't say with certainty if the PMP would help on a long term parking situation if the camera is not disconnected.. it should do what it's supposed to do, that's why they sell it and we buy it. I'm just not going to leave my camera visible in an airport parking garage for a week.
With that said, as I use the parking mode AND motion detection recording, the camera is pretty much recording 9-10 hours straight at work since it always has movement of cars going by. This makes for annoying video reviews but it has not killed the battery, and as far as I can tell hasn't drained the battery to the point of having the PMP kick in.
The DR490L in the Mazda has voltage protection built in so the Power Magic Pro is not needed. I have not put that to the test, though. Same type of recording when it was installed in her previous Hyundai Tucson and had no effects on the battery. It's not currently installed in the Mazda because the car is so compact that I haven't been able to figure out how to fit an add-a-fuse in the fuse box... the fuse box cover won't fit on. So it's not hardwired yet, and I didn't bother with the socket power cord. Need to finish that before winter sets in.
Features included are to your own personal desires. For me, parking mode and motion were what I specifically wanted, and with the purchase of the DR590 also the Wifi capability (more on that below).
The features I've used over the years and my thoughts on them...
Front and rear cameras absolutely, no point in only recording one end of things. Before I ever bought a 2CH system I put individual front and rear cameras in, ran two power wires, had to install/remove two memory cards, etc, it wasn't the best setup to use.
Highest resolution possible in your price range is an absolute.
Hard wiring the power is a must, parking mode is a must. I sure would have liked to of seen what happened when my wife got her brand new Tucson and within 2 months had a nice long scrape on the edge of rear bumper in the grocery store parking lot.... like a shopping card sheared off the edge of the bumper for 3-4 inches.
Motion detection can be useful if you just like to see when something is happening around your car, who's walking by and such things... but if you park in an active area, such as having visibility of a road with a lot of cars going by, it can create a ton of useless videos and be a nightmare to go through if you actually want to try to see something that 'happened'. A few weeks ago a coworker told me someone walked by my car and took a picture of it... so that obviously peaked my curiosity and I tried to find the recording to see if there was anything interesting about the event and I had to search through maybe 200 videos to find the exact moment of the event because of all the motion recordings created from the day.
And the recording itself, if you actually wanted to view an event, is not very useful. The cameras might record X-seconds leading up to the motion and X-seconds after the motion but it doesn't give you an actual recording to watch and entire event of, only those X-amount of seconds. So in my example I barely saw the person walk by, stop, and just off the edge of visibility, took a picture of the car.. I could not guess as what they were doing, or what they did when they were out of view, so seeing it was not really useful in any sense. Just a "hmm, that's interesting" moment.
So unless you are in a secluded area where any motion would actually be something important and worth viewing, I don't feel as though motion detection is a good feature. I don't know if any cameras are advanced enough to have schedules for motion detection, but that would be the only way it could be useful for me personally. Only record at night and not during work hours with 100's of cars going by daily within view of the camera. And remember, parking mode is watching for impacts, so you can't just turn off / unplug the camera when you don't want motion detection.
GPS has only been useful to me to automatically set the time on videos, with day light savings time changes and the possibility of the camera being powered down because of the PMP or taking out the video card and having something messed up with the time, or whatever the case might be, I wanted to have the time automatically set.
Is that useful enough to either buy an addon gps antenna or spend more on a camera with built in gps? That's for you to decide.
Reasons I dislike GPS and/or don't use it for more than the time:
1. The speed recording on the video, I don't use it displayed on the videos. That's my choice for my own reasons.
2. Map recording, generally is turned off with the speed recording, but either way I don't know why I'd want my route recorded. That wouldn't be useful for much of anything. Maybe if you ever think you're going to be kidnapped and murdered in your own car and you think you would need the route recorded to find out who killed you, then sure it might be useful. But the car basically has that built in already with Starlink

3. It's an extra cord to plug in and route and another item to stick on the window. Annoying.
4. It's another cord to have to unplug to get the memory card out, on some cameras, like most BlackVue's.. Annoying.
5. The plugs for the rear camera and the gps are similar enough in size to where if you aren't paying attention you could actually plug them in backwards and not have a working rear camera and not even realize it. Annoying.
I think that's it for the gps stuff.
Bluetooth / wifi connection... I previously had a BlackVue DR590-2CH without wifi, as well as a bunch of others, and bought the wifi version to make it easier to view videos rather than having to unplug everything, remove the video card, take it to a computer, watch whatever I wanted to watch, put it back into the camera, plug everything back in, and hope I didn't knock the camera out of alignment in the process thereby messing up where the lens in pointed.
Any version of camera that lets you avoid taking out the memory card should be considered. It has it's limitations though.
Reviewing videos can be more time consuming than going through all the hassle of the memory card. Using BlackView's wifi camera software is pretty slow to use while viewing videos. The videos are downloaded over slow built in wifi to your phone, that's just not an optimized process... it can take quite a while to try and view videos (think of my example above, I first tried to go through all those videos sitting in the car. It just wasn't possible.
So is wifi useful? Yes, within it's capability and reasonable usage requirements, but it's not good for going through a large number of videos at any given time.
What about cloud access, is that easier? Well, I don't know, haven't used any.. I won't pay a subscription to have that capability, don't feel I need that level of access.
How would the camera upload the videos? Would the camera need to be close enough to a reliable wifi access point? That's not convenient for me.
Does it use another upload capability? It there another fee for that? Do I need a sim card to access a network? lol, that'd be something...
The wifi, at the very least, allows you to align the cameras to the angle you want them. The field of view, height, etc. Without a camera with an LCD screen the only way to really see what the camera sees is to install it, record some video, remove the card, review the video, go back and make any adjustments, and repeat. Believe me, that's not convenient at all. So the live view with the wifi is worth the extra price alone.
Or, a camera with a screen built in, like my DR490L in the Mazda. With the built in screen I don't need wifi or to remove the card to see the alignment of the camera. Watching videos on the camera is quicker and a bit easier also. Thinking of it now, you'd probably want to have a lighter plug power cord in your glove box to use a camera like that for reviewing lots of videos since you wouldn't want to have to reach up on the window constantly to press buttons, and wouldn't want to pull out your hardwired power cord from the roof liner to sit comfortably in the seat with power.
But, screens are a nice option if you can find one that suits you. Obviously they are going to be larger, so that would have to suit your installation needs.
I've kind of lost track of anything else I was going to mention.. I've rambled on enough anyways. Hope my insights are useful in some way.
Whatever you do, get the best camera you can afford with the features you want, even if you think "that's too much for a stupid camera" because eventually you will want a new feature and you'll have to pay again. I bought the DR590 because it was extensive enough as it was without wifi, figured I didn't need/want wifi, and not long after bought the DR590W because I wanted the wifi, have now paid for 2 cameras at twice the cost than if I had bought a wifi one in the first place, and sold the old one for a ridiculously low price not even making it worth buying the new one.
So lesson is, pay for it once, even if it costs an unreasonable amount of money. It will save you in the long run. I couldn't justify the cost of the BlendMount either, but I might reconsider someday on that too.