XD file not syncing

I am getting intermittent, but ongoing issues with my files not synching. I am the creator/owner of the document but my colleague is working on it as a co-editor. She makes changes on her side and when I go to view the file, it says it hasn't been modified for 10 days (the last time I modified it). I know she's done work on it that day. When I access the file, it initially opens, then I get a "Connecting" dialog, then it tells me it's "syncing" forever before it eventually times out. 

This is the third time I've had syncing issues. each time it's been a different error. I know the issue is with core sync, because the last time the Adobe technical guy deleted my core sync folder. I'm just afraid to do this myself for fear of losing something.

This is impacting my whole team and, as we're working on critical COVID projects, is causing a lot of  annoyance and frustration with the stakeholders. Can someone please help or tell me what I need to do to delete my core sync folder, so it recreates itself? Much appreciated!