macOS is optimized for PPIs at the sweet spot in which Asus's 5K 27" (PA27JCV) and 6K 32" (PA32QCV) monitors sit. Asus seemed to be one of the few manufacturers that understand a 27" monitor should be 5K (217ppi), not 4K (163ppi). 4K will show you pixels at most common distances. But if you follow that same 217ppi up to 8K, that leads to 40.5" not 32".
My wife has a triple vertical PA27JCV setup and it's amazing. I've been able to borrow it for short stints, and it's nearly everything I've ever wanted from a productivity monitor setup.