As a Bitwarden (and Vaultwarden) user on Mac/iOS/Safari, Linux/Firefox and Android I have had zero issues with passkeys since I started using them a few years ago.

The first two accounts I switched over to passkeys were my Nintendo and Playstation Accounts as it made sign-in much smoother.

I now use passkeys pretty much everywhere I have the option (at least on high value accounts such as Amazon) and I have not once had an issue. Not having to use a TOTP (or worse an SMS or email based one use code/link!) is much nicer in my personal opinion.

Some sites have a much better designed on-boarding process than others I 100% agree there. I find the sites that do a poor job with their passkey enrolment are the same sites that also did a terrible job of 2FA/MFA setup as well though.

One blessing with passkeys is since I set it up for my mother with her Amazon account she has not once had to ask me to help me reset her password. At least once every 6 months I would have to help her sort things our as she would forget it, reset it and then forget what she reset it to and can't reset it again as she hadn't clicked to update the password in her password manager so it had an old or incorrect password, etc. Always a pain to sort out. Not happened once since switching her to a passkey which is wonderful for me.

Also it is essentially impossible for her to use the passkey on a fake site. Multiple times she has fallen for phishing emails with realistic looking site logins and she would just blindly enter her username and password as many elderly people do.