Hi!
- Affinity is what I use, it's not free but it's a one time license you own for life.
-freephototool is the best online editor I found that has the same shortcuts and familiarity as photoshop, the only drawback is how small the viewer is for the software. I did a short stress test where I created a shitty little fish, I was pleased with the outcome. The selection, masking and layering are pretty much identical to photoshop.