I almost bought an 8k 55" screen for use as a monitor, but I tested a 55" 4k screen for a week and the flatness is what turned me off to it. I've been using three 32" 4k screens in portrait, arranged in a "curved" config on my desk (2 monitors on each side are mounted at an angle), which I really like. But switching to a large single flat screen was not fun.
For me the holy grail of monitors is a 55" 8k curved screen. Not "ultrawide", I want the full width and height and I want it curved, with full 8k resolution. Maybe someday, but I'm not getting my hopes up too high.
I'm not the guy you asked but I have a similar opinion on flat screens. Personally I'd want spherical. ~15" tall and ~25" wide is about my limit for flat screens, anything beyond that I find that the corners/edges are too distant/distorted. My home setup is multiple independent 27" screens, which I like. My work setup is a single flat ultrawide (34" probably?), and I find myself physically leaning my head/body from side to side when I have two windows open next to each other. I have eye level a few inches from the top of the screen, and the lowest couple inches also seem distant/distorted.
For me the holy grail of monitors is a 55" 8k curved screen. Not "ultrawide", I want the full width and height and I want it curved, with full 8k resolution. Maybe someday, but I'm not getting my hopes up too high.