First result for "This will hold" is a blog with the tagline "The truth they're not telling you". So... could you point me to actual data rather than making me read through the raving of a lunatic? I mean, this is clearly a big deal so there must be something solid, right?

the discrepancy in the split between president & downballot voting between mail in and polling-station votes.

• AOC actually did a lot of outreach to her constituents after realizing that a significant chunk of them voted for her AND trump. The gist of it is that it was the same populist movement that trump rode in 2016 combined with "something needs to change". People are a lot less political than we think and they want to vote for outsiders who will drain the swamp. Which is something that a lot of analysts (and people who listen to them) have known since even before 2012 but that was made very very clear on both the left and the right. In a lot of ways, AOC was elected in the first place because of this.
• Absentee ballots have generally always favored Democrats (https://electionlab.mit.edu/sites/default/files/2021-03/HowWeVotedIn2020-March2021.pdf is a good summary from 2021). In large part because it favors young professionals who don't see a reason to wait for election day (more educated. More likely to actually be aware of politics) as well as, people living overseas (who tend to also be more educated), and, funny enough, military people who actually care and have been exposed to other cultures and peoples. This is why trump et al are so against them. And it is why there is generally a blue wave at the start of election night and things then tighten up

the other thing is winning every swing state

Again, actually look at analysis of the demographics. https://catalist.us/whathappened2024/ is a good breakdown but it mostly can be summarized as "men are monsters. whites and hispanics continue to be religious"

As for the rest: I am not even going to pretend "the nazi number came up so it must be rigged" is worth responding to.