I would assume this supervision identity is part of your keychain as usual on macOS and could even be exported. It is not bound to any physical property of that

I would assume this supervision identity is part of your keychain as usual on macOS and could even be exported. It is not bound to any physical property of that particular laptop. A backup should be enough to avoid the scenario you are describing. You should be able to acces the iPhone after importing the supervision identity on any another Mac.