An update on my end:
I ended up just wiping the entire system due to the framerate-issues in DCS (yes, I AM that level of maniac) and reinstalled the at-the-time latest Beta-build from USB. Since that time I've been happily running Win 11 without any issues what so ever, and even gained 3-7 fps in DCS overall. Usually sitting at between 45 and 50 on the ground in Caucasus and PG, about 40 on the ground on Syria. I don't run VR, so cannot comment at all on how that behaves.
Specs: AMD Ryzen 5 3600 on a ASUS TUF B450M-PRO mobo, 32Gb G.Skill Ripjaws V DDR4 3200Mhz RAM. DCS installed on its own 512Gb m.2 NVME SSD, system running on a 256Gb m.2 NVME. ASUS GeForce 1660 Super 6Gb Vidcard, latest drivers. 32" QHD-monitor with a 27" QHD as secondary. No overclocking of any kind.
Have had zero issues with other games (Diablo III, Aliens Fireteam Elite, Battletech, Outriders, Elite Dangerous, Star Citizen etc). Haven't done any direct comparisons between framerates from Win10 to WIn11 on any except DCS, mostly since I haven't noticed any issues in the first place.
Wiped my workflaptop (HP ZBook 14u G5) and installed the release-build of Win11 on it. Zero issues with any of the workloads I have on it.
Take it for what it's worth, but so far I'd have to say that the main differences for me with Win11 are all visual.