I’ve had a 54 incher for 2 years now and I can’t imagine ever going with anything smaller. I’ve got it in a small room too. I just measured it and the screen is exactly 5’ from the front edge of my couch. I would not have a problem upgrading to an 84 incher in that same space.
When anyone ever asks me my advice on TV's, I always tell them that whatever they decide to buy, go with a bigger one........
They usually follow my advice and never regret it........