How do a PC (video driver, OS, apps render image?)

Hello, I am not a developers, but I am interested in that very technical information, because my eyes became very sensitive, and since that time I have been interested in that stuff and am a bit paranoid about it as well. I didn’t find a better place to ask my question.

What finally decides what the PC’s output image should be? Let’s imagine I installed Windows 11 on my PC, but my GPU’s driver supports only Windows 10, what would happen? Could I possibly get improper font rendering/image rendering that can hurt my eyesight? As I know, font rendering depends on both OS and GPU. But what if some component isn’t designed for a specific OS? I can admit, that Windows 11 looks more 3Dish and beautiful compared to Windows 10. I have read about different technologies such as dithering, pentile, black frame insertion, they are basically ways to improve the image by tricking your eyes. But I have absolutely no clue how developers make their OSes look so much better. MacOS also looked far more attractive compared to Windows 10 installed with bootcamp on my MacBook Pro 2013. I have read here posts of people with monitors with reversed pixel order, and they say working with that kind of monitor makes them dizzy since font rendering isn’t designed for that pixel order.

And also, as I know, modern monitors use a slightly different subpixel arrangement, they are slightly tilted compared to the old way of arrangement, where all subpixels were vertically straight. Probably, new operating systems and graphic drivers are also designed considered that, and using a modern PC with an old monitor (and vice versa) is a bad idea?

Thank you a lot for your answer.