Whether I was rested after resting always seemed so chaotic to me.

Also notable - at least if you're autistic, but this probably applies to neurotypical people as well - is that the kind of mental energy that you have available to spend on resting - and thus the kind of restful activity that will actually result in a gain in energy - can vary over time. For example, I may find music restful one day, and find the exact same music exhausting to listen to the next, even if I'm equally tired in a general sense on both days. My theory is that this correlates with what other tasks I've been doing recently (though not in the sense that doing a lot of auditory processing will lead me to 'run out' of that kind of energy - more in the sense that if I've been doing nothing that involves auditory processing, that brainbit turns off, and can't be effectively used for recreation), but I haven't tracked the relevant things well enough yet to do more than speculate.