I also generate them with a password manager. FWIW, I always start with “it’s a long gibberish string” and no one has ever been satisfied with that. I’ve always had to recite it. Anecdotal I know.
But in exchange, my security answers are no longer compromisable online. I think overall it’s a positive trade off, but that’s just my hunch.
KeepassXC already has this feature [1][2]. It can also store and generate OTP codes and works with YubiKeys (similar to Bitwarden Premium).
There's also a popular Python script called xkcdpass [3] which does the same from the command-line.
[1] https://keepassxc.org/images/screenshots/windows/screen_006....