"The gears of justice grind slowly but finely."

He's attempting to outrun those gears by stalling with lengthy appeals and getting back to the presidency before they catch him. The appeals process ostensibly exists (in theory) to prevent cavalier judges and vigilantism; at the same time, Trump is a career veteran of stalling the courts, and the rich have the luxury of being able to afford doing so.

I agree that he's an obvious criminal and has gotten the lightest treatment possible so far, but it's also worth recognizing that he's functionally a mob boss with tens of millions of followers, all with a tenuous grasp of reality and an undying love for their demigod.

Even if the judges aren't afraid (and some assuredly are), they have to perform this delicate balancing act so his followers don't cause a mistrial through their sheer stupidity.