Well, that isn’t actually true. We know state systems in some states had their voter rolls hacked. That wasn’t intended to actually change votes, it was to hump up precincts and create confusion and long lines, due to people’s data being deleted, changed, modified, etc.
States reported that happening in highly dense Dem areas. Those stories slowly trickled out over those 4 years. All that matters is that they fixed it. There were no reports this time around.