I've been using triple 4k monitors for a few years now, also been waiting for 2160p SUW. As a mac user I think 4k is the minimal requirement for HIDPI to work properly. Also after years of wear, three monitors are degrading to more and more different color tones. Having one 2160p SUW can basically satisfy all my needs. One good news is 8k tv is now available, I'm thinking getting a 8k gaming tv and split it vertically into two 2160p SUW or four 2160p 16:9.
I also play games on windows pc using this triple screen setup, my current pc has 6800XT, with FSR enable triple 4k gaming is quite feasible. Most recent AAA games can run 50-60fps with high preset.