What is the max number of cores/threads Cubase/Win10 can now use? (eg. Ryzen 2990wx)

I am building a new system after my last CPU died. I have gotten into additive synthesis in the past few years using my own designed synths. Each one can only be on a single thread at a time of course and can be very CPU intensive per thread. Therefore for me it is important to have the max number of threads/cores, so each synth can get its own thread/core and I still have room for lots.

I was reading this thread here:
https://www.steinberg.net/forums/viewtopic.php?f=283&t=147175

Which suggests some changes have been made to “improve” core utilization. But it doesn’t say about whether it can fully utilize all the cores.

An AMD Ryzen 2990WX has 32 cores and 64 threads. How many of these cores or threads could actually be used?

Also, is it correct that the current issue is due to Windows 10, and if one were to downgrade to Windows 8, all the threads and cores could be used without limitations?

I want to get this clear so I’m not wasting my money expecting something that can’t work.

AMD ryzen does not perform great compared to intel on Windows.
The threadripper performed much better on Linux, so there seems to be something in the Windows kernel that prevents Ryzen in general to perform well under Windows in low latency situations.
http://www.scanproaudio.info
Has a review that is worth reading.