Error messages unfortunately can be both vague and incorrect.
For example, end users using Windows 10, at times during an update / upgrade got an error message that the computer was not capable of running Windows 10.
If your willing to perform trial and error testing I'd like you to see whether this is the case.
1) Make a free backup image:
(Acronis, Aoemi, EaseUS, Macrium, Paragon, etc.)
2) Upgrade to Windows 11 bypassing the CPU requirements
3) Perform an in place upgrade repair
a) run the compatibility checker > post images or a share link displaying the results
b) perform an in place upgrade repair > post images of any error messages or codes
4) When you've completed the testing select the go back or continue using Windows 11
At any time you can restore an image and return to Windows 10.
If you're willing to perform the testing some links can be posted into this thread.