The web is the only saving grace for any of the upstart mobile devices and new operating system projects, when it comes to compatibility with incumbent/major apps.
That's also why open protocols/APIs/formats, data portability, are important. So that people who care can write an independent clients. One of the banks I use has an open, docummented JSON API for end users (as a basic feature of the regular bank account, that everyone gets access to by default). I can easily write a bank app for that, to be able to do some basic account overview and wire transfer payments.
It's not a locked down platform, so if security means that everything has to be signed/verified/locked down and unmodifiable by the user, then it will not pass.
It means you get the freedom to choose a different pre-approved proprietary app to access your bank account (which will probably make its money from selling a nicely detailed advertising profile based on your transactions), not the freedom to interface with your bank with an open API.
Also, because of the strong authentication requirement from PSD2 (amongst others), you won't get to do banking in an app except on an Android or IOS smartphone. Add to this the ongoing drive from banks and governments alike to push authentication even on a normal computer to smartphones (i.e., you use their proprietary app on an Android/IOS smartphone to authenticate when you access them via a web browser on a normal computer), and the picture becomes really bleak for any alternative smartphone OS.
The current trend, at least seen from the Netherlands, is: you submit to an Android or IOS smartphone, and you get to do things like banking or accessing your digital healthcare dossier online. If you don't, then you are classified as digitally illiterate, and are nudged towards having people near you assume those tasks in your name by delegation — basically the strategy for elderly or the mentally incapable. The third option, authentication using discrete hardware such as card readers (currently an option for many banks) or something like WebAuthn is something banks would really like to get rid of because of the cost of maintaining multiple authentication methods, and hey, everybody owns an Android/IOS smartphone anyway, so why not .. ?
Very useless, unless you just want to give your data to more third parties.
In addition EU also broke all my bank scraping scripts (except for the mentioned bank, that still has the same API it had for years already and doesn't require two factor auth, just an api key) by enforcing two-factor (well not really, just SMS auth, it's not like I can use any other 2nd factor, or make my own).
So in addition to helping third-party data slurpers, they also broke the first-party data access with the latest regulation.
It's not the EU enforced API (that's not intended for end users anyway - I tried asking other banks for API access too, and failed). This bank had this API for years.
Right now the performance is better than on my pinephone but there are also some issues, like Libertine not working correctly.
The main issue with anbox right now is that video/audio playback does not work. Apps like NewPipe and AntennaPod run fine except that no playback is possible (results in blackscreen).
Dual booting a linux distribution with something like glodroid seems like a promising solution!