If your goal is to find a mentor who can encourage you, which category would it fall into?

It depends what subject and things like that, if it is to encourage you. you could find motavotional speakers on youtube

Mri or anything that has uv lights

Well if you pick a machine to work on and that's gonna be your exercise if you don't stick to that machine your muscle strength your muscle mass rather will change because you haven't been doing it you change something in your exercise routine which changes your body's form of dealing with things for example you might become weaker or stronger depending on what kind of exercises you do in whether or not the machine you picked actually your muscles grow.