Depends on what you actually want to do, because Photoshop is an all-trick-three-legged-pony, whereas the alternatives are all "we need to do X, and we need to do it well, let's actually make that application instead of something as insane as Photoshop".

Krita, Clip Studio Paint, DxO, aseprite, there are tons of great options if you actually want an application that was written to be "what people who want to do X want in an application", instead of trying to be all things to all users.

The Affinity suite is quite decent, among them Affinity Photo would be the Photoshop replacement. It‘s fast, easy to understand, a pleasant UI and has all the features you need.

Affinity’s iPad UI is quite nice and relatively full-featured as well.

Affinity Photo is probably the best option right now.

Yes- Affinity Designer is also really nice for vector graphics. But they are just clones.

If you are looking for „next-level“ check Nuke (The Foundry)- unless you are painting.

Nuke seems to be a 2D-3D/video compositing application. That’s bringing in a huge amount of complexity if you’re trying to deal with 2D still images. It’s an Adobe After Effects competitor, surely?

Yes it is a postproduction tool and built for compositing but even for still images it is light years ahead of photoshop. It is also rock solid and extremly fast. Simple stuff such as writing a png is 100 times faster.

Isn’t that for video compositing and costs thousands of dollars?