I use Pinta for basic editing, I mostly do cropping and annotation.

For mor complex stuff Krita and Inkscape for the annotations.

Looking for the holy grail?

I hope immich is successful and collects a shitload of money and increases it's processing capabilities. I'd be happy if it could rotate a photo without losing all exif data and moving it into a different location.

In the meantime, you could look into digikam

Gwenview when it's really small.

Now I'm thinking why don't we make an image editor that we can customize the simple UI. Like users choose which sliders and tools to put on the ui, it'll be simple UI with like just 5-10 buttons/sliders/tools, but you van customize it to have basically anything. That way you can simply drag drop tools make new UI and then use it for specific use cases.

Maybe already existing tools have that options. Or maybe we need to make a new one, in that case, it'd be nice if we could just add all different tools in dlls or sth, so that you can only download/keep the tools you use.

Check out Shotwell. Its editing functionality sounds exactly like what you're looking for, although it is designed for managing a library of images videos.

$ convert --help