I mean, the actual trial would be a shitshow either way.
What the Republican claim is is that the Democratic counties took steps to improve the mail-in vote process (Specifically, if you sent in a vote where you made a silly error like printing your address in the wrong location, they'd send you back a notice saying that they couldn't accept the ballot and you'd have to fix the problems and try again) while the Republican counties refused to make similar improvements. Because Democrat-led counties improved their systems and the Repubicans didn't, it was unfair to Republican voters, therefore the Democratic counties should have their votes thrown out.
The judge was openly confused as to why he was suing the counties that did improve their systems, rather than the ones that refused to.