I use ProtonPass on every device I own (religiously) and have never had an issue. But it's because I'm very careful to only deal with any credential ever via ProtonPass.

I can imagine it gets annoying very fast if you accidentally put a passkey in the wrong place, ie because Chrome proposes it's own credentials store.

ProtonPass also lets me export the private parts so I'm not stuck as with some passkey managers.

Passkeys are great but require you to understand some things about them, and you need discipline in dealing with them.