I do the same with three but all in portrait mode.
That's an interesting idea. I should look into that when I eventually upgrade. A stubborn part of me left the monitors in landscape because I occasionally play games, but I end up never doing that on my desktop.
Because I prefer to use the same model of monitor when doing a grid, so I don't think I want to add to my existing setup, because my monitors are discontinued, and they're displayport only for 4K60.
I think they have more than a few years of life left in them, but I'll definitely look into a configuration like yours at upgrade time.
Since aging has forced me into wearing reading glasses, I wear single vision computer glasses that are optimized for the distance range of my monitors' closest and furthest points.
Because I dont have scaling enabled, I don't get any of the HiDpi issues that I've gotten on my laptops with Windows.
I have found that I am still wanting for even more screen real estate, and for a time I had a pair of ultrawide 23" monitors underneath my main monitors, but it created more problems than it solved and I recently went back to only two monitors.