This is exactly what iCloud Keychain does, except (unless it’s changed recently?) you can sync it peer to peer too, you don’t have to store the contents in iCloud.

The only part it’s “missing” is a 2FA TOTP generator, but apps like https://cooperrs.de/otpauth.html work quite well in that regard so it’s not a major pain point.

Safari + (iCloud) Keychain is IMO evidence that good password management can work client side - these “alternative” solutions like login links via email etc are basically catering to the shit experience of other browsers/platforms.