I am more a PSP than a PS guy and I really tried to use GIMP for my image editing needs on kubuntu. I even ran a pinned patched version of it fixing the save/export "bug" (Another boneheaded ideological dev decision).
A few months back I wanted to add a few straight lines to an image. In PSP these would be vector object that can be adjusted in size, color and position. In GIMP not so much. It has only the pencil tool with an alt mode holding shift that does straight lines.
However I needed to adjust the lines distance from each other slightly - What followed was a lot of cursing and repeated attempts, switching to the path tool followed by discarding that idea and switching to making a layer per line. After finishing I deleted what I had done and did the same by starting PSP 9 in WINE in about 30 seconds.
I did some googling and found the reason why GIMP lacks any useable Vector functions is that vector functions belong in a Drawing program not a Manipulation program. And GIMP is the latter. This is a paraphrased from memory quote by a GIMP dev.
That probably means that not putting any vector function in (even though stuff like the Text function really benefits from vector layers) was a decision long ago that passed into ideological canon by now and is probably a huge task to implement.
So I am currently back to using a PSP version from 1998 for editing images on ubuntu. Even though its buggy as hell. Newer version after the Corel acquisition sadly come with a DRM service that balks at wine. I have licences for a few of those I would love to use.