I think it's pretty dangerous to trust either side fully 100% on this - however - what always got me thinking something fishy was going on was (and USA election nights I sit up all day/night here in the UK essentially doing a 24h shift) is that Trump looked comfortably ahead in 3-states that he ended up losing by a few hundred thousand when the counting was magically finished after breaks that lasted a few days
Nothing fishy about it. State laws prevented some states from counting absentee ballot votes until election day, even some...not until the in person polls were closed.
Trump told his followers to vote in person on election day...with no covid precautions...
Democrats wanted constituents to vote safely, with no covid virus risks so they promoted voting via absentee ballot.
When the polls close, the first votes counted and released to the press, are election day results, then the early voting results done via voting machines, then the absentee ballot votes, then the military absentee ballot votes from overseas.... it goes on for days, to count all the votes in every presidential election...
The process to count absentee ballot voting is a much longer process than through the electronic voting machines.
The counters have to verify each absentee ballot envelope for various things...
Is the voter a registered voter, did the voter request an absentee ballot, does their signature match their voter registration signature on file etc... many states have put in electronic scanners that do signature matching now so it can go quicker in big population areas...
Anyway, only after the outer envelopes are verified, and counted for a total number of absentee ballots are returned, are the envelopes then opened and their ballots removed from the developed, and unfolded, can these ballots be run through an optical scanner to count these votes....
Trump leading early in the electronic voting counts from election day was anticipated by everyone because democrats discouraged voting in person Due to potential virus spread.
The news and everyone said it would be a few days before we could announce a winner, knowing that 50% or more of the votes were going to be early voting, and absentee ballot voting and not section day voting.
Trump played with his follower's heads and began seeding that the election day votes should be the only votes that should count and the winner should be announced on election day, bull crap.....
The rest is history....