Protocol-wise the difference is that a TYH* requires an interaction by the user.
An app generating OTP codes is a TYH while the secret used to generate the token is a TYK.
A password manager is a TYH while the passwords inside are TYK
In general every (non-quantum) TYH possess some kind of TYK that can be used to duplicate the TYH.
In the name of security sometimes there are locks around the TYK, sometimes physical other times software.
In the case of passkeys the inability to export them makes them TYH.
* "Thing you have" is too long