MacOS 4k Monitor Performance Issues? Here's Why 

This was super helpful. I was noticing some odd graphical hitches (M3 Pro MBP 14", 12 CPU cores, 18 GPU cores, 18gb ram) when using my external 3840x2160 32" display when the internal display wasn't showing the same issues. Thanks!

Oddly I went from 2 LG 32 UN880s running at 4kx60hz (thinking they looked pretty good), to a 48" LG Oled, again running at 4k, 120Hz. I have noticed no real downside using the apps I normally used for work, just the bog standard Microsoft Excel, Word, Powerpoint, etc. Adobe DC Pro functions fine as well as a few specialty apps. I just bumped up the icon size and font size for those on the desktop and all's well. I did notice a small problem with the mouse cursor. At the default size setting, you could indeed lose the mouse on this size of screen and resolution. I bumped up the cursor size and did notice a little less accuracy. Just not enough to go back to a smaller cursor. After close to 2 years using this monitor, I wouldn't trade it. Yes the PPI isn't in the "good" range but I don't notice any downside. An added bonus is that most movies look better on my 4K OLED monitor than the 75" LG TV I also have in the room....