You’ve clearly never run hackintosh. MacOS runs better than Windows even on PCs not made by Apple. The difference is especially obvious on Laptops, where MacOS gets almost as much battery life as Linux, whilst Windows barely gets about 2/3rds as much

MacOS has 25% market share for desktop operating systems in the United States. That counts as mainstream to me

MacOS had that feature for a long time, it’s pretty intuitive. I’ve never heard of someone thinking it’s a bug despite MacOS being very mainstream nowadays

If you want to edit photos then Affinity is passable, and GIMP is a joke.

If all you want to do is draw, then Krita is a very capable alternative to Photoshop, but being good at only a specific subset of Photoshop capabilites doesn’t turn it into a replacement for it

Sadly there is no alternative that is even remotely as capable

I prefer micro