As someone using 49" ultrawide (3840x1080) for a few years for office, gaming and simming, I feel like going from triples to ultrawide is a step down in terms of immersion. But a step up in terms of graphics (and fps) as well as saving some actual space in the room.
I wrote more in-depth about my experiences here:
Also, “The Sim Simma” on youtube runs 4 x 4K 55" but the side ones are in 2K, to save some performance. He seems happy with that.
I’ve even heard of some running sides in 1K just for performance. “The Sim Simma” tested it, but found it didn’t improve but it degraded quality.
I will likely be going 3 x 4K 55" myself, sides either 2K or 1K depending on FPS. Front may even also be 2K, depending on pixel density and performance. And then I’ll go up higher as I find money to upgrade to better GPU some time long in the future 