I’ve been thinking about exactly this for a long time. My only thoughts are you should check out helix to see what you can learn from them if you haven’t already, and you should post or dm me the repo so I can see if there’s anything I can help with!
One thing I’ve been thinking about in this area is you could make the “plugin system” completely compiled. Users would have some toml or .rs file they would change and point the rust compiler at a directory and come out with a new binary. You could still add in a “Lua plugin” plugin which enables lua-based plugins without forcing all users to pull down the gear required to use that in rust. It would also make it possible for people to create various “distributions” of the editor with varying complexity and size depending on user needs