I have a fp6, with /e/os. I use all the things you list. Android auto only just started working in limited ways, but you have to follow a doc from murena release notes to get it working. Basically you have to install a few Google services. After that, the digital assistant still doesn’t work, so you can’t respond to texts and stuff but everything else works fine. Proton apps all work great, in fact proton VPN is on the F-Droid store.

Banking apps vary, but my bank works great.