For starters remove the items in the corner. Nothing there serves a purpose. Add pictures of the whole room (in a comment) and you’ll get lots of ideas from pros.

Thank you Anne. Here are pictures with all the items removed.

I would leave that space empty. Every corner does need "stuff'.

Can take pictures of the other 2 walls: one behind the sofa and the one behind the chair which may actually be open.

I'm thinking the TV may be best moved to the left somewhat and then a chair may go in that corner.

Can you stand back far enough and take a pic of every wall of the room so we can see what the overall lighting plan is here? How is this room lit in other areas?

I too find nothing wrong with an empty corner. Less is more. Your room already has great colors and a welcoming vibe.

Since the corner and the room in general are dark. I would add a nice taller floor lamp with adjustable light fixtures in that corner. If you want to add a plant after that, make sure its one that isnt quite so tall, and that has a good sized pot. I also agree that the tv could be moved over to the left quite a bit, and then a chair would work there, and maybe also a smaller table with a lamp on it.