GrapheneOS has been basically flawless for me, most of the time I forget I’m even using a custom rom. Using the Aurora Store, along with a few select apps in a work profile with sandboxed Google Play services goes a long way in terms of plugging the usability gap. I know there’s supposed to be issues with banks, but at least in my anecdotal experience, I’ve used accounts from 3 different banks and haven’t had any issues.