This looks really interesting. I will try it out sometime, but since there's no Windows builds (does it even support Windows?) that will wait a bit. I don't think it's good idea to have compile-time configuration (needing a toolchain to change config). What happened to MERC[1]? I suppose it was written for this editor?
I personally don't think Lua is a good choice for an embedded language in 2024, the bare minimum should be indentation-based scopes and zero-indexed arrays. Of course, Tthis is your project, but perhaps taking an existing and mature language would ease the adoption?
[1] https://ki-editor.github.io/merc/