I switched away from Ally bank for similar reasons, on my lineage’d pixel 5 with gapps, their app would always fail the login the first time then succeed the second time for no reason.
Then the bank I switched to, greenfi (coastal community bank) completely blocked login unless I had play protect (in Google play) enabled, which allows Google to uninstall any app from your phone without asking if they decide it’s a “security risk” or whatever - I can totally imagine them deciding that ReVanced / morphie / patched apps that block their ads to be a “security issue”. Luckily greenfi was more understanding and they did something that allowed me to log in again.