I think it's weird you seem to be ignoring everything that's happened since 2020. What have those undecideds done in the last 3 elections since 2020 to everyone with Trump's backing?
I wouldn't read too much into one bad showing. Not happy with Joe's effort there, but I take a little comfort in the clear distinction in party health on the two sides though. Biden has a bad night, people are asking questions, having the hard talks and addressing the issue. The denial is on the other side. When Trump behaves like his waist size and IQ are interchangeable, when he 's completely lost or tries to pretend taking the Montreal Cognitive Assessment is a badge of distinction, all you hear from the magats is crickets or praise. He stayed in office despite the 25th Amendment, and he's running again despite the 14th Amendment. As image goes, Trump is the one in the hole. Maybe if Biden was responsible for making women second class citizens or the avoidable deaths of over 760k Americans we'd see a bit more parity. He's a convict, a rapist, a traitor, an insurrectionist, not to mention some weird kind of wannabe groupie for brutal authoritarians - the same people he'll roll over for if they say nice things about him. One of these decades American conservatives need to learn the meaning of 'conflict of interest,' I hope it's sooner rather than later.
I don't think there's as many undecideds as some peope are saying. Pretty much everyone I know, across the political spectrum, wants Trump to DIAF. With the females it's at 100%. You don't see libertarians
booing and heckling Joe Biden. He'll bounce back.