No, when a State has record low rejection rates, the burden of proof is on the State.
I can guarantee if Trump won because a record number of ballots were rejected, the burden of proof would be on the State to explain themselves.
The fact these States have fought independent audits, is telling. Take a random 10k sample of mail ins along with envelopes for signature match, from across the State and let an independent commission audit. Very simple, should have already been done and gives public transparency.