Presidents, including Trump, have basically had immunity the entire time, all he had to do was not publicly attempt to incite an insurrection, but if put to the legal test, the answer is obviously "no they don't". He might not even be wrong about some of the ramifications of spelling it out like this, but he's the one forcing it, because as usual, he gives no fucks about anyone that isn't him, and upsetting the apple cart is a small price to pay for a small chance at an advantage.