I've seen the same thing. What I've seen is most of those folks that supported them during the campaign are now pretty quiet. During the campaign it was "cool" to support Trump and the republicans but now that the dude's in office, most are seeing that campaigns are very different from the administrations.
Looking back I blame the Democrats for running horrible candidates and the gaslighting that their candidates were actually great and were as "cool" as the Trump team. It just felt so disingenuous when you heard Democrats saying that Biden was still very with it and even more disingenuous when they said that Harris/Walz were a great pick. And now the folks that said it was disingenuous were not wrong, cause after the campaign ended and Trump was in office seemingly everyone that praised Biden and then Harris then flipped the script and started saying what everyone was thinking all along (that Biden was not fit to serve and Harris wasn't a great candidate).
I talked to alot of guys that flipped from D to R this past election and just about every one of them said a version of: "do they think we are stupid??".
The Democrats have a hubris problem, they think that just because they run someone and tell folks that the person is great, everyone will just automatically buy into that. That's just not how it works and you have to make a genuinely convincing argument and that argument can't be "the other guys is worse"