I'm in Europe. This is true here. Unvaxxed are pariahs. That's why Macron got away with saying what he did.
Going back to the SC behavior during the legal moves against voter fraud, I'd say Roberts is the kingmaker.
He allowed Brandon to be appointed POTUS, and he can also take him out if TPTB think Brandon is fucking things up too much.
My take is Sotomayer and Breyer were so over the top on purpose. The knives are out for Brandon. Sotomayer and Breyer bullshit can be used to justify a no mandate majority decision. Even if those two are that stupid, I don't think they'd get past top legal minds advising them.
Long story short, I don't think there are any legal/constitutional considerations at play, only political. Make some non-precedent setting decision to keep a universal mandate threat alive, under the correct conditions, going forward, but stop the OSHA specific mandate specifically to bitch slap Brandon. I don't think Hillary was mouthing off about Brandon just for shits and giggles. She's in the zone and locked in.