Do I Need a New Microwave?

With Russ away so much during the weekdays I usually just microwave some leftovers for dinner. I am trying to eat smaller portions to counteract my DJT weight gain. To ensure this happens I use a small salad plate as my dinner plate.
I have noticed that even though I have less food on a smaller plate my microwave takes forever to heat up my dinner. I am not sure if it is actually takes longer and I don’t remember how long a microwave really takes or if my microwave is getting less wavy.
I know nothing about the science of how a microwave actually works. I am sure I could Google it, or search on YouTube for a tutorial on microwaves. I’m just going on my gut that two and a half minutes for a small plate to get lukewarm is just a whole lot longer than it used to be.
What I am wondering is am I doing myself any harm using a slow microwave? Could the radioactivity, if that is really in there, leaking out all over my kitchen?
I don’t have that much to do these days so having my dinner take three minutes rather than one is no big deal, unless I am killing myself. Now comes the big question, what kind of microwave do you have and do you recommend it? I don’t need a fancy one or a built in one, just a simple machine to sit on the counter and heat my small dinner.