The reason microG didn't help is that it's solving a different problem. It reimplements the Play Services APIs, so push notifications and maps come back, but it can't produce a Play Integrity verdict — that needs an attestation signed by Google and tied to a locked bootloader and the device's hardware keystore. Banks almost always check MEETS_DEVICE_INTEGRITY, and nothing running in userspace can fake it.

So "a bank whose app works without Play Services" really means "a bank that doesn't call Play Integrity". Annoyingly that's the question to ask them and nobody in support will know what you're talking about.

On the 2027 verification thing driving this: from what's been written about it, it applies to certified devices, which means ones shipping GMS, and non-certified ROMs sit outside it. If that holds then degoogling removes that worry rather than racing it. I haven't seen Google state it in their own words though, so I wouldn't plan around it yet.

I recommend this list for a (non-comprehensive) list of banks that work without GApps

Otherwise check if your bank offers a website. Thats usually an easy way to get around the dependency.

edit: and check if your bank will work with MicroG instead of GApps

In Portugal my bank app doesnt require Google services, but some (other) payment app do.

Check https://plexus.techlore.tech/ for the apps that you use

Lineage have stated they won't be adding it to their ROM. But I understand the sentiment and I'm on the journey myself. Microg will be the next thing I try.

Bank with banks that have websites and that work on desktop-computers. Are you going to install an 'app' for every company you want to do commerce with? Things have become quite absurd.

Consorsbank does online banking via web and hardware generator. Their app works on GOS with sandboxed play services.