Yes. Several things.
The close proximity causing problems with natural eye-development. It's causing more children to have problems with peripheral vision and long-distance vision.
The social aspect. TV is (or used to be) watched together, you talk about what's on, react together, explain the subtleties and context to children that might not have picked up on it, talk about what might happen in the next episode, or what happened in a previous episode to explain why something happened, and lots of other comprehension skills. Tablets/phone is an individual activity. There's no opportunity for that.
The actual production of content. TV programs are longer, sensibly paced and based around a storyline. YouTube/tik tok crap is short and produced purely to be addictive. It's a dopamine hit, but it doesn't last. There is no value to it.
Posture and core muscle strength. TV your most likely sitting on a proper seat, maybe not rigid and upright but at least your head/neck are at a natural angle. Tablet/phone you're hunched over.
Awareness of surroundings. TV because your vision allows you to see the room, you are aware of your surroundings. If someone walks in, you see them. If someone talks to you, you hear them. Tablets/phones you zone in to that tiny screen and block out your surroundings so are unaware of what is happening around you.
Obviously, that's a general picture and there will be specifics that don't match that, but yes, there is a big difference between TV and hand-held screens.