I use Linux but I am not sure how to write an autostart for it.
Sorry.
Try this website for help:
https://vswitchzero.com/mystic-systemd/
It's how I autostart my bbs when I'm running on Linux.
|11ogg
|11SysOp, Altair IV BBS
|11altairiv.ddns.net:2323
... There are three kinds of people: Those who can count, and those who can't
--- Mystic BBS v1.12 A49 2024/05/29 (Windows/64)
* Origin: Altair IV BBS (21:2/147)