Its on the roadmap. AFAIK it requires vector layers before it can be worked on.

have you tried this?

--export <game> Exports specified game (requires --dest)

You are supposed to use /var/home/user instead of /home/user in your paths, scripts, etc (or /var/$HOME). Im not certain on the why but iirc its because on immutable systems only /var is writable so anything writable has to be under it.