We do expect any of the latest versions to work with Monterey. Could you please try to reproduce the stuck sync and report a bug of your stuck sync via the Dropbox app? That way I can take a look at some logs.
Please excuse my ignorance, but I can't find an option in Dropbox to send a dump/bug report to Dropbox. When I select View Sync Issues, I get a popup saying there are no sync issues. When I open the Dropbox app, all I see is a Finder window with the Dropbox folder.