First, which version of 'buntu are you using ? I am avoiding kubuntu 26.04 at the moment because of Wayland and some of the old stuff I consider essential.
The git hub/ bookchk pages are not very well layed out. As you state you get the impression that make is the way to compile and it is for Gimp 2.10 However for Gimp 3 meson is the way to go. Again for anyone reading the post https://github.com/bootchk/resynthesizer...rom-source.
I might make a 26.04 VM, get Gimp from the PPA and try a compile.
For some sort of inpainting, you are not stuck. There is the gmic_ginp_qt plugin http://www.gmic.eu with several inpainting filters (just that I prefer resynthesizer)
The git hub/ bookchk pages are not very well layed out. As you state you get the impression that make is the way to compile and it is for Gimp 2.10 However for Gimp 3 meson is the way to go. Again for anyone reading the post https://github.com/bootchk/resynthesizer...rom-source.
I might make a 26.04 VM, get Gimp from the PPA and try a compile.
For some sort of inpainting, you are not stuck. There is the gmic_ginp_qt plugin http://www.gmic.eu with several inpainting filters (just that I prefer resynthesizer)