TL;DR: Traditional desktop and server editions of Windows 11 have surprisingly high system requirements, making it impossible to install newer versions of the OS on older PCs. However, Microsoft has released a more compact version of Windows for IoT devices, theoretically providing Windows enthusiasts with Enterprise licenses new modding opportunities.
The IoT editions of Windows 11 are the "superior" choice for older PCs
In context: The Windows IoT Enterprise OS family comprises the Windows editions Microsoft sells to companies for "small-footprint" PCs, point-of-sale devices, and other embedded appliances. Previously known as Windows Embedded, Windows IoT editions are straightforward to install, even with hardware components Microsoft doesn't officially support.