[mdb31]

> There is no sync to provider servers on any TOTP implementation I use

That's hard to dispute, but will you accept https://guide.duo.com/duo-restore as a counterexample?

> Are you perhaps referring to the Google Authenticator or the Microsoft Authenticator apps when you refer to TOTP

No, I'm referring to the actual RFC 6283 TOTP protocol. Which uses a trivially-cloned single private key. Which is, see the example above, in fact trivially cloned 'for convenience' by at least one widely-used 'enterprise' security solution.

> What makes you think they don't "securely" make a few duplicates themselves?

Since that literally makes no sense if you know how hardware tokens work.