Exercise never really gets easier, either mentally or physically. Even as a fairly neurotypical person, it’s always easier to not work out than to work out. There’s logical rationalizations that it’s good for you and if you work out hard enough maybe your body will see fit to reward you with some endorphins, but it’s only “habit” in so much that it’s good self-discipline. I wouldn’t lump it in with stuff like brushing your teeth at all.