I use the Adobe Production Suite and never encountered any UI scaling issues. Curious about what's different on the MAC.
Re: Monitor calibration, I'm afraid this is more Apple misinformation/misinterpretation by users. All monitors need to be calibrated regularly (if you care enough to be accurate for professional level work). The idea that you can get a MAC monitor which is calibrated from the factory, calibrates itself, and/or will remain calibrated is just not true. While there are "tools" and utilities in either OS or in the monitor itself to help the user calibrate it is, while better than nothing, not good for professional applications. You need a monitor calibrator. I have calibrated many many MAC and PC monitors and can tell you that MAC's come out of whack from the factory (need calibration) as do any mega-expensive professional displays I've ever worked with. Granted some are much better than others, but calibration depends on environmental factors (hardware age, ambient light type, temperature, position and source). It's all pretty complex in scope, but critical. Fortunately the tools simplify the process by making it repeatable.
Shiro, please understand that for most folks, the standard display presets are good enough, but since I know you're doing the digital art stuff professionally, I thought you'd like to know.