Windows 10 20H2 feature update causes lags, freezes, slow performance

I Have The Same Problem after The Update...

Some testing here. Most of my apps have some sort of Chrome (which is based on Webkit) in the background. Lots of apps, including Discord and Slack use Electron as their backend, which runs on top of Chrome.

So, I switched my browser to Firefox. No lag or stutter, so I switched. These apps (perhaps more) do:

Task Manager
Steam Friends (but not Steam itself)
Chrome
Edge
Discord (Electron)
Slack (Electron)
Spotify
Facebook Messenger
VS Code (Electron)

The commonality between these all, except perhaps Task Manager, is the webkit base.

Here's a recent related bug https://bugs.chromium.org/p/chromium/issues/detail?id=1061465 but I suspect something Microsoft did is still the culprit underneath, since this did not happen until the update.

Here is my two cents on this matter.  All of this is IMHO and not based on any cause and effect.

I have been dealing with a system slowdown for weeks hoping an update will put it back the way it was in Jan.

My metric is using the Mouse panel in Settings. It can take 3-10s for me to make a change in the cursor speed. Sometimes while sweeping across the screen the mouse cursor will stutter or halt for a part of a second and then jump a short bit. I guess to catch up. Note that the  old fashioned Sound control panel does NOT have that slowness problem. It works great. Clearly they don't make software like that anymore.

I have done a cleanboot, and that stopped a small amount of the lag but it is still there. I can't see anything in Task Manager that is doing large amounts of CPU work. I see this lag when Task manager says the CPU is 3% busy. I say Windows is wasting some time in a way that is observable but not detectable by the CPU use. I am not doing any of the DISM or Upgrade junk. It has taken many hours of my time doing that six times in the last two years and NEVER helped.

I am waiting as this will just go away or morph into a better or worse symptom after one or a dozen updates.

Same here but it disappears after restarting. Interesting.

Same here. Installed the update last night, no problem before then. Afterwards, every time I switch a window it lags for a half-second. I've uninstall and reinstalled every driver I could think of including graphics, network and pointer devices.