Not on iOS but I like my yubikeys. Depending on your requirements (if you have less than 32 TOTP accounts per yubikey), they can handle your TOTP directly instead of just using them to unlock Bitwarden.

For security I don't like to keep my TOTP keys in my password manager, even if it is strongly protected. With a yubikey I can ensure that both access to the key AND a physical touch is necessary to generate any codes. So even if I leave it plugged in on a remotely compromised PC I'm mostly protected, because a touch is required.