I will agree a sectional is not the answer there and for sure not with a chaise. How many seats do you need every day? The dining chairs need to be put away unless needed . I assume the chair you show is one of the pair you are planning to upholster ? I think maybe think about that choice since reupholstery costs as much as new often . Without seeing the new sofa there is of course no way to know in this case. That TV stand is holding the TV too high for sure. I need pics of the whole space and also the measurements of that space on a floor plan to scale . I think I agree that is a weird space but with no idea of the size it is hard to tell. Post the plan here in jpeg format in a comment the extra pics too DO NOT start another post.

It's right here........

The dining chairs are there since I hosted my book club the other night. Usually in a different room.

I think those chairs, although unique, are too tall for your space. and will block views and light.

Not usually my first choice, but the TV might need to go over the fireplace. You can get a mantel mount that will lower for viewing and raise when not not in use.

From mantelmount.com

I live alone, so this space is used maybe 1 or 2 hours a day at most. Entertaining would usually be 6 or less, except for my book club once a year where I host about 10. But I can pull in chairs from other spaces for that.