I have accounts on lemmy.world and lemmy.ml. After launching the app, when adding my account I’m presented with some common instances to select from. After choosing one, I enter my credentials using 1Password. To add the second account, it’s a completely different process, and I can’t use 1Password for the username.
Similar issue on Android for me. Google passwords is also terrible for it. It says it saved a password when I sign up for an account on an instance, then it says there isn’t one when I try to login, then I manually search through passwords and select the one for the instance and it says incorrect(google might be saving my email as the password).