Hi, I just started with win11 host and workstation 17 this year.
I noticed that win10 guests are slow when installed with hardware compatibility = workstation 17!
I ran an excell VBA code with some database queries as a benchmark and it took about 75 seconds to finish.

When I downgraded the HW compatibility of this Win10 guest to workstation 16.2 the same macro took only 9 seconds to finish!!!!
7 times faster on the same guest on the same host only changing the guest Hardware compatibility

So for me I stay working on WS17 with WIN10 guest @ Compatibility = WS16.2!!

I stay away from running a win11 guest (needs HWcomp = WS17) this is also a verry slow combo for me. 
(Even though I speeded all up with regard to disabling Hypervisor mode ULM an all other win11 tweaks.)