The way I see it, the only way to reverse the results of the election is to prove without reasonable doubt that it was schemed. That is to say that there was a coup by the Biden team with help of State election officials to tamper with the election process in his favor.
Trump will not be able to convince the courts to reject all votes after the polls close. Each state sets the rules by which citizens can submit their vote. So long as these rules are respected, there is no challengeable issue since it should have been contested before the election.
He might challenge the results based on the lack of meaningful access to observers. But then you get into a debate about what "meaningful" means. Whether or not that is enough to reverse the decision of the American people through vote is highly unlikely. The fact is Trump and Biden had observers in all precincts. No one was denied access. They did have to maintain I believe it was 20 feet from the counting area. The legal aegument here is super flimsy.
Recounts aren't going to overturn thousands of votes. Recounts are going to happen in PA, WI, NV, AZ and GA. From what I read, ballot counting machines have become very sophisticated and so the chances of a software error are next to nil.
In short: expect nothing more than recounts being ordered but that won't change the result.