common.themoviedb.org scraper version 3.2.5 updated by Team Kodi Member @olympia Looks like it fixes the artwork download problem.
I download the zip file from here – Files... and installed it. So far so good.
So I just posted a new thread which is basically this issue. There is already a workaround for this on Matrix and another PR was created (which worked for me ) in kodi to fix this… Hopefully we can backport this to OSMC
Just an FYI that the scraper updates will address any new media you scrape, but existing media will still have references to http instead of https. So if you go to change the art on stuff you’ve scraped previously, there might still be issues. While the Kodi team works on a more global fix, refreshing the scrape should get you new art with https references.
Reading the GitHub comments you linked it should be possible to fix your problem by editing the m3u file or installing a alpha version of kodi where you have a toggle to disable http2