Password managers aren't nearly intelligent enough to be used without copy and paste for sensitive forms.

One example is how almost every password manager including the built-in one in most browsers will assume that if there's a type="password" field, then the previous sibling field must be the username. Sometimes they'll even pick a field far away in the DOM like your chatbox input to autofill with the username.

So imagine a form like this:

    Amount to transfer: <input type="number">
    From account ID: <input type="text">
    Confirm password: <input type="password">
    <button type="submit">Submit</button>

I found that there's no good hackless way to allow a password manager to autofill the password without touching the other fields with a username or some other quirk like just clearing your inputs. Even a fix like opening a modal with the lone password confirmation field doesn't necessarily fix it in all browser/OS configurations.

Password managers are braindead and browsers don't give you any tools to help.