There's a piece of software called Waydroid[1] that allows you to run Android applications on GNU/Linux platforms - including the PinePhone. Sxmo, despite its name, can run Wayland instead of X and therefore supports Waydroid.

Personally, I haven't managed to get Waydroid to work, a task hindered due to some massive initial downloads which are required to set it up. However, I haven't tried particularly hard, and there are videos online by those more successful than me[2].

[1]: https://waydro.id/

[2]: https://tilvids.com/w/2b2f3a24-ae23-458e-a0fd-2f24a185a11b

For "security" reasons banking apps generally disagree running on anything rooted. Is there a way to circumvent that?

While some banking apps do this, I wouldn't call it common. I have ~10 bank/brokerage apps on my GrapheneOS device and they all work just fine.

Workaround for me is to change bank then. Would love getting away from iOS spying on me.

Don't use a bank that demands an app instead of having a website?

I haven't used Linux on a phone yet so I don't know about those, but regular rooted android has easy ways to circumvent what you're talking about.

Generally, in order to run bank apps on a non-stock ROM you have to root your phone and install things that hide it, kinda defeating the purpose.