Gimp was never meant to do those kinds of operations, and it still can't - at least not "easily"; it's still as cumbersome as before.
You can still do "pixel level" editing - you just can't do primitives.
Honestly, though, it's not the right tool for that.
If I need to do vector art, then I'll use a vector art program like inkscape. If I need to do CAD, then there's a number of options in that space as well.
If I need to do pixel level editing, or something similar, my go-to editor on Linux is:
https://en.wikipedia.org/wiki/GrafX2
...mainly because I'm familiar with it since it is virtually a clone of various editors I used on my Amiga back in the day.