I hope I can be excused if I don't sum up the entire problem directly here (are speed complaints accepted?)
It's just that this looks at least the same problem I experienced in doitsujin/dxvk#1845 (apitrace inside!)
Except that the performance hit from the uncached occlusions doesn't look as strong, because even when I stare at the empty wall with nothing behind framerate is already almost half of what I'd expect to begin with.
p.s. are reports from W10 still legit? dll version 10.0.19041.3636 doesn't even seem like a proper build number