Yeah you could just switch to Linux on an old PC like that

The stuff that Microsoft is making mandatory for Windows 11 is hardware security features older hardware is more vulnerable to malware that runs at deeper levels of your system

If you want to be secure at the hardware level...or at least more secure at the hardware level, you need newer hardware

Core isolation for example won't work on hardware that's incompatible with windows 11

A lot of malware can't run on a Windows machine once core isolation is enabled. Like I always say, if it won't run with core isolation enabled, it's probably malware