Registry keys and autoattend.xml config keys are not clever people finding a way, it's people using stuff Microsoft put there to do just this for now. I.e. Windows 11 has not been strictly enforcing these yet, they are just "officially" requirements so when they eventually decide to enforce in a newer version (be it an 11 update or some other number) they'll then be able to say "well it's really been an official requirement for many years now, and over 99% of Windows 11 installs which has been the only supported OS for a while now are working that way" at that time. If they just went straight from Windows 10 to strictly enforced Windows 11 options it'd've been harder to defend.
Windows 12 will close the loophole: your CPU will require a signed code path from boot down to application level code. No option to disable Secure Boot or install your own keys. But there needs to be an installed base of secure hardware for this to happen, hence the TPM 2.0 requirements for Windows 11.
Registry keys and autoattend.xml config keys are not clever people finding a way, it's people using stuff Microsoft put there to do just this for now. I.e. Windows 11 has not been strictly enforcing these yet, they are just "officially" requirements so when they eventually decide to enforce in a newer version (be it an 11 update or some other number) they'll then be able to say "well it's really been an official requirement for many years now, and over 99% of Windows 11 installs which has been the only supported OS for a while now are working that way" at that time. If they just went straight from Windows 10 to strictly enforced Windows 11 options it'd've been harder to defend.
You're missing the point, the TPM 2.0 requirement is there to drive adoption, not to actually prevent you from installing Windows 11.
Windows 12 will close the loophole: your CPU will require a signed code path from boot down to application level code. No option to disable Secure Boot or install your own keys. But there needs to be an installed base of secure hardware for this to happen, hence the TPM 2.0 requirements for Windows 11.
Since Windows 12 hasn't even been mentioned yet, I wouldn't worry about what you're describing at all.