PowerQuery hangs forever in refresh when multiple computers are used to edit

I'm having a sudden problem in which when I make edits on another computer and try to refresh PowerQuery on my primary computer, it refreshes forever or sometimes refreshes for hours before throwing up a random memory error. Normally, the refreshes take between 3 and 10 minutes. I've used this setup for a year now with no issues before last week.

I have an relatively elaborate PowerQuery setup that pulls in shared data from many sources, including online, Dropbox, SharePoint, OneDrive, and in-workbook excel tables. Lots of merges, lots of custom formulas. All file locations are variable parameters that are changed via a dropdown in Excel.

I do most of my work on an up-to-date Windows 11 version of Excel running on a Mac via Parallels. The other machine I occasionally edit on is another up-to-date version of Excel on Windows 11. They are synced via Dropbox.

At first I thought my VM was corrupted, so I reinstalled fresh. It worked fine until the next time I edited on another machine. I've deleted all PowerQuery and Excel caches and it still happens.

Nothing I'm doing is new, so I'm not sure why it suddenly breaks.

Any thoughts?