Lightroom Classic error with video import or playback since 10.1

I use Lightroom to organize my photos and videos from my DSLR and iPhones and modify and export my photos. 

I recently updated Lightroom Classic to 10.4. I'm not sure what version I had been using previously, but it had probably been a year or more since I last updated. After updating, I realized I could no longer import any videos into my catalog. In fact, I discovered I could not play any videos at all that were already in my catalog. Ocassionaly, I would get an error such as "There was an error working with video" or "Video System Error: Unknown message: nextFrame". 

I hunted for any hints of how to fix this, including purging my dynamiclinkmanager, dynamiclinkmediaserver folders and my video caches (in-program and manually). I restarted my computer and Lightroom Classics 10.4 multiple times, and tried a fresh reinstall of Lightroom. I tried to eliminate any plug-ins or modifications at all. I tried using a new a catalog. I tried uninstalling and stopping any other programs that I thought might have an effect on the video. 

Finally, the only thing I could get to work is downgrading to version 10.0 (trying each step on the way down). I have no idea what was introduced in 10.1 (and beyond) that is not compatible with my PC running Windows 10 (up to date) with modern components (Nvidia 3080). This is adequate as a temporary fix to this problem because I can at least continue to import and organize my photo and video library, and continue to use Lightroom for photo processing and export. But it means I likely cannot use any new features introduced after this point. 

Please let me know if there is something else I should try. Thanks.