No idea which device you have but as for Samsung, i run an S20+ 5G (bootloader unlocked etc) and have 0 issues with any banking app ive ever used. Just to give you hope. And giving hope goes against my central edicts....as does spoonfeeding
As for tips :
When in doubt, start with stock ROM....
The next could have been harvested from the last 5-10 pages...you should practice reading the last few pages of a thread, its a good habit as XDA isnt your own personal helpdesk where you only post when you have a crisis - without reading the room, because often its not just you having the issue, and we collaborate to fix issues....
You'll almost certainly need (along with reading the first page of this thread) this:
Thats currently the best option to deal with the recent (as in last few weeks) change from SafetyNet to Integrity Check, and you should bookmark that thread for any future changes.
And you'll want to check you can pass this (top 2 out of 3 green is good enough)
Get info about your Device Integrity through the Play Intergrity API
play.google.com
And thus you have reached the extent of my pity....i now return you to the normal programming from me, which is pure unadulterated indifference to the plight of man as a whole. Enjoy.