Here's a link to a recent article from a major, respected Japanese newspaper, stating that Subaru is halting development of all plug-in hybrid vehicles:
asia.nikkei.com
A few outtakes from the article:

Subaru to halt development of plug-in hybrid vehicles
Japanese automaker accelerates shift to electric cars

A few outtakes from the article:
Subaru currently offers a plug-in hybrid version of the Crosstrek SUV, but starting next year, the Crosstrek will no longer be available as a plug-in hybrid.
Subaru has been selling the plug-in version of the Crosstrek for $36,845 since 2018, but sales have been sluggish, with only 2,600 units sold in the U.S. last year, less than 1% of Subaru's unit sales in the country.
Subaru will focus on the development of EVs as the company plans to invest 250 billion yen ($1.8 billion) for the development and production of EVs over the next five years. In 2027, Subaru will build an EV factory in Gunma, north of Tokyo. Subaru's current EV offerings are developed with Toyota Motor, owner of a 20% stake. Subaru, however, is likely to develop EVs on its own going forward.
I guess that means that the Solterra will be the company's compliance car for the next year or two, and we've got a while to wait to see what Subaru has up its sleeve in terms of EVs.For hybrids, Subaru will take advantage of its partnership with Toyota and use the Japanese auto giant's technology. It plans to release new hybrid models around 2025.