They are not too low. I see no need for a third.

I would reverse the positions of the tree and the floor lamp

Lower the two pictures over the sofa

No, they’re not too low. I like them. But there’s too many items on that wall. I would dispose of that storage item (??) with the handbags hanging off it on the far right and then unsqueeze the rest of the stuff on that wall.

I’d center couch/art (height is fine). Can floor lamp and shelves go elsewhere. I’d move plant to corner and add a small side table/lamp there instead. The wall will feel less busy and better balanced.

Replace your handbag shelving with something like this that you can hang in your entryway.

As others have suggested put plant by the window and lamp where the plant is now. Art is fine. Just center the sofa and have the two pieces centered over it.