This could be a problem that might require for the engine to be removed from the mounts, remove the pan to repair the treads on the pan itself, I inserted a pipe reducer with sealant in the pan with a nut on the inside of the pan to make sure this plug does not spin, then install either a plug or, buy a brass drain valve from John Deere which, opens to drain the oil in the future, this plug would take the wear rather then the treads of the pan.
I would like to keep the rework of the pan treads to a minimum because of contamination to the oil system.
There are tapered drain plug available to perhaps fix your drain problem on a temporary fix until you can take the tractor out of service to repair it the right way.