[yoklov]

Alternatively, write most of it in C++ and allow it to be extended with components written in script, ECS style.

Or something else.

Honestly, having too much scrip is very much a thing to try and avoid. Perf (gc, etc), long term maintainability (usually no static types in script), tooling (frequently no debuggers, profilers, or the ones that exist are low quality), etc are all reasons for this.

If you're going to have 90% lua, you probably should be writing the game in lua anyway...