I'm sick of post-mortems too, but...

[TwilightZone]

3. Biden won voters who had a union member in the household 57/40.

So, unless there was a huge shift for 2024, the assertion about unions doesn't hold up.

https://www.statista.com/statistics/1184429/presidential-election-exit-polls-share-votes-union-membership-us/

I think many of the others fall into similar categories. They have some validity, perhaps, but not as much as those who had the opinions might believe. Some are just right-wing talking points, which you identified as such.

For the record, Hillary would have won if not for about 100 things going right for Trump. He needed them all and got them. He needed slim margins in a few states to swing the EC, he needed a third party to draw just enough votes in swing states, Comey influence, low turnout, 30 years of RW propaganda, apathy on the left, potential campaign missteps (WI, etc.), and on and on and on.

Had any of those been marginally different, the outcome may very well have been different, as well.

The assertion about Biden's approval ratings has some validity, but any candidate we put up was going to be tied to them.