Firefox Android (and iOS it seems?) actually supports autofill for other apps, one just needs to enable it: https://support.mozilla.org/en-US/kb/end-of-support-

Firefox Android (and iOS it seems?) actually supports autofill for other apps, one just needs to enable it: https://support.mozilla.org/en-US/kb/end-of-support-firefox-lockwise https://support.mozilla.org/en-US/kb/end-of-support-firefox-... (I've used it quite successfully when it was in a separate app called Lockwise)