I have had same problem off and on. Have Windows 10 Pro, using current Edge browser. Have had this issue in the past, and for no apparent reason it cleared up and desktop Notes started successfully saving notes, saying Edited and then Saved, with time date stamp every second that I changed the note's content. Now nothing updates - last time it updated was 3/15/24, after that - nothing. Tried multiple solutions, none were permanent, powered down PC and waited overnight, no fix - previously when I closed the browser and reopened Edge, it would begin saving current edits again, but not for the last 2 weeks or so. Not happy with Apple for not being able to fix what should be a straightforward sync issue.