I think the general phenomenon is often talked about under the umbrella term "zoom fatigue" - besides the fatigue this also encompasses stress and anxiety. (https://spectrum.ieee.org/zoom-fatigue)
Personally the best improvement was closing the camera feed, and that has been my team's experience as well.
There will be extremely few meetings (mainly HR and meetings with external vendors) where we set the camera, and even for those you can do the opening and presentation with camera on, and just shut it after that for the meat of the discussion.
The biggest part is we're presenting documents and slides either way, so seeing the person's face somewhere just doesn't help. In particular we want to check the meeting transcript realtime to be sure it matches what we're talking about. Overall I've seen no downsides doing it since the pandemic, and don't see going back to camera on meetings by default.
It's become a bit of a meme now: https://youtube.com/watch?v=Dl0rpDY9460
Personally I've yet to find a cure :P
i believe one problem is that in online meetings and phone calls pauses are more awkward and uncomfortable. that means people avoid pauses to think before they speak, which makes online meetings more rushed. which would explain the feeling of GP after a meeting.
the question is how to make online meetings more relaxed.