Pixelmator - 1000%. Native MacOS - quick to load and very intuitive layer-based paint interface. It's a one-time purchase for $50 but they used to run sales.
They were bought by Apple recently but still sell it. I moved to it when I migrated away from Photoshop. It doesn't have some of the fancier stuff like puppet mesh warp, but for an all-around editor I'd argue its unrivaled in the Mac space.
Very actively developing this project, so hopefully it'll become a suitable replacement relatively soon. Please open GitHub issues or PRs if you have specific requests, happy to help.
They were bought by Apple recently but still sell it. I moved to it when I migrated away from Photoshop. It doesn't have some of the fancier stuff like puppet mesh warp, but for an all-around editor I'd argue its unrivaled in the Mac space.
https://www.apple.com/pixelmator-pro
EDIT: Krita is also great (and free) but it feels more geared towards digital painting.