I'll try be brief - but I've looked into this a tonne over the last 3 or so years. Still not settled, but I've definitely now found the best solution *for me* and possibly others.
I've tried a bunch of big screens. All sorts from 16:9 to 21:9 and even 32:9
Resolutions from 3440x1440 all the way up to 5k2k (and 5k1.4k)
All have their pros and cons.
Always easier to take a look right?
So that is the samsung 49" 32:9 which is effectively 2 x 2560x1440 monitors glued together. Indeed, this room runs a trashcan, so it effectively sees it as two separate displays. New macs see it as a single.
It works well here - since it allows vertical space for a center speaker (focals were chosen for their height in this case!) and room for an ok size client monitor (though we are trying to squeeze a 65"+ inch in there now)
Same size (I think a slightly different model) in another room.
Never worked great in there. The lack of vertical space when working just didn't suit the workflows in there)
Interesting - you can see here how the low profile nature allowed a bunch of other gear to be able to go in the room - which is tiny.
Here's another room with 43" and 55" client monitor (set back a bit)
The height of the screen meant the screen is actually set LOWER than the desk (hard to see, but you look down to the bottom.). Not ideal, but did work surprisingly well. The 4k native res of these 43" monitors is excellent, especially if the monitor is a little away from your eyes. In this case the screen is between the speakers, which for acoustics is EXCELLENT (and far better than getting reflections off the back of a large monitor)
While we were building out another room with a small neumann 5.1 system. (Kh110's). I'll try find a newer pic later - but here we're using a 34" 3440x1440 monitor. Its mainly used for editing atmos / dialog, and does the job nicely. Sure, more res would be nice, but we had the monitor already, and that made the decision easy. There's now a 50" TV monitor in there as well - the neumann C needed to be flipped onto its side to make room. Again, not ideal - but for the operator, its not an issue. (It changes horizontal spread, but being in the sweet spot means this doesn't become an issue).