I dont agree with many things apple does at all, and I also think their password manager has flaws like revealing usernames without authentification.
It is pretty handy though, to have a file where the entries are stored unencrypted, and if the password manager detects an entry it prompts to decrypt exactly that field, maybe with a fingerprint.
KeepassDX needs to run in the background and be completely unlocked to even detect apps or password fields.
Do you know any existing app that can do this?
Use KeePassXC. Audited, code, open-source, highly customizable, zero cloud stuff.
Yes I already use these. On Linux I use Kwallet, store my huge random Keepass password in there and unlock the Keepass database by fetching that password using a shortcut.
But still, then the password storage is open. Not as elegant as an on-demand password requester, especially on Android