It is very simple, if you cannot change their rules, use them against them. The GOP must have a vote harvesting machine of its own. In blue areas they will never harvest enough, but I suspect in areas where the Republican was ahead on election night, that might not be the case.
It appears the GOP was ballot harvesting in North Carolina.
Rs cheating to counter balance Dems is not the solution.
Might as well just have shootouts and determine the winner by whoever is left standing.
In order for the USA to survive, elections must be clean and honest.