Hello @B. James keown
The main reason for not being in the list of not compatible devices is not because of performance, but because of security reasons. One of the main focus of Microsoft in the Windows 11 version is towards security and protection. Most of the processors not compatible are because don´t have TPM, TPM version is below 1.2, and other low level architecture flaws that may expose your system to certain vulnerabilities.
As well, there are some methods involving registry changes, to proceed with the installation on not compatible devices (I have seen installations even on CPUs as old as 2006), but please check the next article to be aware of the supportability:
https://support.microsoft.com/en-us/windows/installing-windows-11-on-devices-that-don-t-meet-minimum-system-requirements-0b2dc4a2-5933-4ad4-9c09-ef0a331518f1
Hope this helps with your query,
----------
--If the reply is helpful, please Upvote and Accept as answer--