It's wildly obnoxious that browsers don't let you generally suppress these prompts.

And if you take the nuclear option and strip your browser of WebAuthn support, then you obviously can't use any passkeys, which doesn't work for me - I have two sites where I do want to use passkeys (because it's the only way to avoid SMS-based MFA on every login), but I never want to see passkey prompts for any other sites.