KeepassXC is a good client that lets you handle your data how you want. I wrote a pro-Passkey blog post here[1] that explains how to do your own syncing, though I later discovered Passkeys are explicitly built to support proprietary software vendor lock in and had to revoke my support. If you are concerned about being able to control your own data outside of the big tech ecosystem, I strongly recommend avoiding passkeys entirely. It is possible for now, but they are not built for that and the spec authors are actively hostile to you managing your own data.

[1] https://www.smokingonabike.com/2025/01/04/passkey-marketing-...

I also meant to mention that many Keepass clients support Passkeys already today. Strongbox on iOS and macOS has similar or better integration to 1Password/BitWarden. Windows you probably want KeepassXC for now as it isn't fully baked in mainline Keepass. I don't know what you'd use on Android today, but I'm sure there's at least one and probably more on the way.

Bitwarden is free, and if you are concerned about these terms changing, the excellent self-hosted open source server implementation "vaultwarden" [1] supports passkeys as well.

[1] https://github.com/dani-garcia/vaultwarden

The Google / Chrome sync is free