The basic premise is that Trump was winning on election day, only to lose overnight as a flood of fraudulent ballots washed away his lead.
This is completely mistaken.
It is now clear that just 54% of voters voted "in person", either early or on election day. 46% voted by mail/absentee.
66% of Trump's vote was "in person", but only 42% of Biden's. That's why it appeared that Trump won on election day.
Most of Biden's vote, 58%, was counted after the polls had closed into the next day(s) because it was absentee/by mail. He had a larger reservoir of his voters to draw on than did Trump, whose post-election day reservoir was only 34% of his vote.
There were doubtless more fraudulent votes cast this election because so many of the ballots were absentee/by mail, and so many more people voted and voted this way. The problem has been proving it, and proving it was large enough to flip places like Georgia, Wisconsin, and Arizona.
Absentee/by mail ballots typically post high rejection rates for voter noncompliance reasons: failure to sign the envelope, failure to return it on time, failure to mark the ballot correctly, failure of the signature to match the record, failure to show a return address matching the file, and much more. These rates typically exceed 1%, often by quite a lot. The problem is rejection rates in this election are coming in much lower than 1%, which, contrary to the Democrats, is a huge red flag.
Investigation of these problems should have been Team Trump's number one objective in challenging this election. Unfortunately and characteristically it got side-tracked by craziness and laziness, the hallmarks of the Trump era. Pieces of paper are evidence. Fanciful theories using computer "data" are not. Courts are not interested in jeopardizing their claim to impartiality by facilitating fishing expeditions for one political party against another. Either you've got the goods, or you don't.
It's sad Trump is such an incompetent and wasn't ready for this, but it is what it is. All the "shouldas wouldas and couldas" in the world ain't gonna fix it.
Buh-bye.