“Lazy” 2 year old

So my first, 4, is really energetic and wild. He has ADHD so he is very active all day every day. So maybe I’m just comparing this to my 2 year old, but my 2 year old seems “lazy” in the sense he is really not all that active in play. His favorite thing to do is just sit on the couch and read books or do ABC Mouse on the iPad. He will watch TV too. He also loves to color quietly and not be bothered. If we go outside he kind of just walks around, pushes around a dump truck a little, but is soon done and wants to go inside. If I sit down and play with cars or dinosaurs on the floor with him, he’s only really interested for about 10-15 minutes and then he wants to go back and relax. He loves to just sit with me on the couch. Is this just his personality? Or is something wrong? My 4 year old is constantly playing, independently, dancing, screaming, never has any interest in a screen or sitting down.