I have a good experience with running 64-bit versions of Windows 7 and Windows 10 on various Core 2 Duo/Quad CPUs (slot 775) on various chipsets for many years. Also old GPUs work without troubles (needed because these CPUs don't have integrated video), because operating system can use older drivers. The only real-world limitation is RAM size. 4 GB is possible but not good for 64-bit Windows 7/10, 6 GB is much better (2x 2GB + 1x 1GB DDR2 module).
And although internet is full of information that these old CPUs cannot run Windows 11, several people reported they actually can run W11, it is just not officially supported by Microsoft. (I did not tried myself.)