Hi D, maybe I can help with this.
In the Plugin Menu in Google Sheets, you can select “Fetch Data” and also select “Reset Fetch”
This deletes the Data in your Spreadsheet in fills in the Data from your Shop.
Now everything should be in sync.
If you now select Sync Data, all the row where the “OK” in the Sync Tab is removed will be written to the shop.
So fetching is for getting Data from the shop and syncing is for uploading data.
Have you tried deactivating all other plugins?