I was in the same boat as it turned out the highest 1.78:1 corresponded to the widest 2.35:1 I could fit. I also play lots of games and watch more 1.78:1 and 1.33:1 content going with the largest 1.78:1 I could fit gave me the best of both worlds.
The bars weren’t bothering me with burgundy walls but I put up some temporary curtains (old stuff from the apartment) until my new ones arrive and can already tell that once I’ve got full black curtains around the front of the room I’m going to need to make some masking because with everything else so dark even the slightest boarder is now becoming visible.
The masking will be easy since for 2.35:1 stuff I shift the picture down to the bottom of the screen so I will only have to mask the top.