Hi,
The bottom line is, the unsupported processors does not have a feature called VBS, which is a requirement for Windows 11, even though it supports TPM and secure boot. If you enable VBS aka Memory Integrity from Windows, you would see a reduction in performance, hence Microsoft decided not to put it into the list of compatible processors. You can install manually, but it is not worth it as Windows 10 continues to be supported until 2025.
Also, Windows Security Director explains in detail in this video:
Understanding Windows 11 new security requirements with David Weston - YouTube
Additionally:
- Windows 10 is supported until 2025.
- As long as security requirements are met except the processor, you can install Windows 11, offline if you understand the risks including no updates. See:
Installing Windows 11 on devices that do not meet the minimum requirements