Finding a suitable replacement head unit for a newer ('19-20) Subaru could be tough, at least for a while. I own a `19 blubaru (different model) and there aren't many suitable replacements I've seen that don't offset out from the face of the dash. You might have better luck with the Outback, though.
The reason I asked about Apple CarPlay is because my headunit (not as nice/advanced as the Outback's) is light years better for navigation when I use Google Maps through ACP. Playing music that is on my phone is nice, too, and it can all be controlled from the dash touch screen. I also use Sirius primarily, due to getting a really cheap plan. ACP might be limited to iPhone 6
S and beyond, though.
Without seeing exactly what's going on (media, file structure, etc.), it's hard to offer suggestions without leaps.
A deep dive into youtube may prove helpful, too. I've learned a lot about the functionality of my car there. There's always the the manual.
I kid.
Best of luck with figuring out whichever path you take.