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
It depends on what you do
Well the obvious answer would be all the professional Photoshop capable things man, we can love Linux and still admit there’s areas for growth
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