qBittorrent official forums

Assuming the problem was a CPU single core bottleneck, the only other thing that might help is disabling hyperthreading in the BIOS to make each "core" Windows sees be roughly 2x faster.
Then qBT would need fewer threads -- 8 or 10 instead of 16 or 20.

It may be that hashing pieces is the bottleneck, and that may not be easy to make into multiple parallel processes. (Libtorrent's core logic may not have even done so yet, not sure...)

A question. The people who develop the software of qbt, enter in this forum to see the possible problems that the software may have? Or do we have to climb it to the github?

I have not had the opportunity to test it with the configuration of the 20 threads.

Sledgehammer (main dev for qBitTorrent) doesn't check the forum as much as he used to -- what little spare time he has seems to be used trying to make the qBT changeover to a newer version of libtorrent, boost, and C++ compiler.