>Windows 11 is running on my ThinkPad T530. Its CPU is very nearly 14 years old.
Yes, you can bypass HW checks to install it on a pentium 4 if you want, nothing new here.
>What is missing here that was present when this same computer was running Windows 10?
All the security features I listed in the comment above.
So, if I'm hearing this right:
This computer had the security features that you listed while it was running Windows 10, and now that it is running Windows 11 it is lacking them?
(I'm not trying to be snarky. That's simply an astonishing concept to me.)