Server low cpu usage with PAID FOR WHOLE CPU preset

Hi, I have set my server to use the PAID FOR WHOLE CPU preset for initial pregen but it only uses ~4cpu. Is there a custom preset i have to make to get this to work? CPU has 20 threads so it should be fine from my understanding.

cpu is 13500
64gb ram, 32 dedicated to server

Thanks and sorry if this was asked before, havent found anything similar