I do think you are right. There is this part of Trump attraction that is heavily influenced by the idea that someone is taking something away from you or attempting to. This they really cling to. Money, status, guns, religion, jobs, the pecking order they were comfortable with...whatever. There is this belief that they, the MAGA core, are under attack, and there is an entire system built around it to repeat the message. Over and over and over. Everything is an assault on them, trying to pry some piece of their existence away. 

Trump is the whiner in chief. He leads the pack with complaints and grievances and this is, I think, why he is so adored. They bond with his constant complaining. It is why his legal problems benefit him, it confirms in their mind that he is under attack and through that, that means they are under attack. 

Basically, being in a courtroom is better for Trump than being on the campaign trail, it is one long commercial confirming to his followers that they have to fight the evil that is the deep state, Democrats, Republicans that are not loyal, and what they see as a corrupt justice system. He can't generate this kind of excitement on the campaign trail, doing his bizarre rallies, but he can standing in a courthouse. Then every media outlet puts him on TV for free. 

Honestly, there has never been a candidate that gets this much free air time. It's nonstop every day.