The story here isn't that Trump doesn't understand magnets, it's that he was transparently told to say something by a donor associated with John Deere and he fucked it up because he didn't understand it.
Yeah the best part is that he jumped from elevator magnets and how they stop working when they get wet, to something about they should have stuck with John Deere. His cognitive decline is very real and accelerating quickly, and likely being fed by all his legal issues and knowing that there is a very good possibility that if he can't get himself into the white house he'll never be a free man again.
It will be interesting if they use his deteriorated mental state as a defence when he is found guilty in any of these criminal cases trying to get him a lesser sentence.
I said it years ago, after it became clear that punishment for Jan 6th was going to be slow. Trump won. He shat all over our democracy and its people, pillaged the country as much as he could. And by the time any real consequences reach him, he will be too far mentally gone as to be meaningless.
It will still mean something to him as long as he is mentally aware enough to have any sense of self, as the narcissist is strong in him. Once his cognitive decline rids him of that sense of self he'll just be a confused angry old man, but he won't have that drive to be a Dictator and rule anymore.
It would actually be kind of interesting if he declined in such a way that with that sense of "self" disappearing, if he would actually feel any remorse for being a piece of shit to anyone and everyone around him before it all just slips away.