A simple stone world replacement mod for NeoForge 1.21.1. Select StoneBlock as your world type and the overworld becomes solid stone. That's the core of it.
Tested with All The Mods 10 Lite — loads clean, no conflicts.
Each player is supposed to get their own spawn room at first join, spiraling outward from center at 1000 block intervals. The code is in there but multiplayer spawning hasn't been fully tested yet — use with that in mind.
Author: Kotawolf License: MIT — free to use and include in any modpack