It doesn’t appear that your Sync time is the problem so removing Virtual Columns is not going to help. It looks like there is something significantly slowing down your Purchase Order processing.
If you tap on the binoculars, you can drill in deeper to see more precisely what is taking up the time.
More than likely, you have selection expressions (SELECT(), FILTER(), etc) that are performing inefficient table scans.
EDIT: OH, and by the way, it seems you may not have “Delayed Sync” on. With it off, a full Sync is performed after EVERY change. This may be why it appears its a Sync time problem. Try turning it on and see what the performance is like then. You still need to look at the Purchase Order processing because it is WAY to slow!