If you use macOS because you need to run Mac software, then you probably aren't going anywhere.
now i'm back to linux because i can't stand the decisions apple took. plus, it feels like osx (now macOS) is less and less table on every iteration. i had a BSOD while trying to plug my external monitor ffs.
Inkscape and Gimp are the stalwarts, but for someone coming from Sketch or Photoshop they feel quite ancient and somewhat messy.
https://www.figma.com is cross-platform (web based), and a pretty good Sketch competitor
For a Lightroom replacement, Darktable is actually quite good (though I really miss the high quality shadows/highlights algorithm from ACR)
Since the Linux release of SD I've been dual booting elementary on my desktop and have had a pretty solid experience. For me it's games that make me keep a Windows installation around.
They're actually claiming I'm going to give up Photoshop, Pixelmator, Lightroom, CaptureOne rather than buying an external card-reader. And that's ignoring that most of us already prefer 3rd-party external card readers for speed alone ..