It isn't a huge mystery why Biden is unpopular at the moment, or it shouldn't be, but the Discourse is run by people who are in covid denial and who think because people echo obsessive media complaints about inflation back at pollsters that the fact that the federal government is Too Damn Generous is the problem.
Covid illness rates are huge, death rates are high and climbing, life is in no way "normal." A lot of uncertainty, no cushion, and no sense that any help is on the way.
You can blame who you want for this, or perhaps no one at all, but if things suck the guy in the White House generally gets the blame.