Because it's not Federal Trump has no immunity in GA, irrespective of whether he's president or not, this trial will take place before he could ever be in power, if he's found guilty there is a madatory minimum sentence of 5 years, though that could be anything from jail to probation
GA Governor is in power to 2027, he's never letting Trump off with anything
Parole board, whilst possible I doubt they go against the Governor and other senior GA officials in a matter like this
The Orange rat seems immune because he's been allowed to get away with things his whole life, he's never been held accountable and that makes him think he can do what he likes, he's now finding out that actually some people will hold him accountable