This is really cool. I never got to play with a proper NeXT machine, but WindowMaker was my window manager of choice for several years in the late 90s/early 2000s. I always wished that GNUStep could have gotten more traction on the desktop.
I love the NeXT aesthetic, I'm ready for the the next UI design trend to go retro.
You might want to take a look at https://github.com/trunkmaster/nextspace where someone tries to recreate the NeXT experience on top of noth GNUStep & Window Maker, both modified to provide coherent experience.