How to fix sync errors in macOS Big Sur?

I have the same problem - I've lost an entire library for my biggest client. I've been trying to get help for over 6 months and Adobe customer support are utterly USELESS. I've spoken to over a dozen agents, wasted around 2 weeks worth of hours on chat, remote connect etc. Almost every agent has had to be told the issue right from the start, and they've tried the exact same fix, funnily enough with no more sucess than the previous agent. And today I get told the issue is with Big Sur, not any Adobe application. At which point I asked if this was an issue for all Big Sur users, and then the response was amended to "no its just your computer". Yet I have no custom hardware or software settings. My macbook is less than a year old, and the issue existed on my iMac 2011 which was certainly not running Big Sur. So anyone who actually has a clue, and a real answer - please step forward!

I'm having the same problem here. Files not syncing on BigSur. Frustrating....

if sync'g stops on the same file, the file is probably corrupted.  fix or delete that file and retry sync'g