The types of people protesting the lockdowns the hardest aren't the types who will switch to Biden because, unlike Leftists who believe America is one solid empire with a shared soul defined by the superhero who sits at the top, they seem to have a better grasp of states' rights.
The people who hate the lockdowns remain on Trump's side because his public-facing remarks have been on their side and he's saying his hands are tied, and the people who like the lockdowns will hate him no matter what so it's not like he can say anything to change them.
This is why, during the debates, Biden was completely unable to provide a coherent problem with what is going on. He was, at once, saying Trump is to blame for the lockdowns being in place, but he is also to blame for not doing more severe lockdowns. Nobody can really come up with what anybody should be doing differently, and the issue is so globally confusing I don't think anyone really hates him for this.
Even to the average voter, the Dems pinning every single Covid death on Trump like he personally slit their throats sounds preposterous. I think their goal was to get him to slip up as much as possible and say Covid is fake or go off on pre-existing conditions but he didn't really take that bait like they wanted so now they're stuck with "Donald Trump killed 200k people."