OldYLevels

Changes the Overworld height to the old Y range, 0-256. This will basically crop off parts of your world if you don't pregenerate the world on an earlier version of the game.

OldYLevels is a free Minecraft Java datapack. Compatible with Minecraft 1.18, 1.18.1, 1.18.2, 1.19 and newer. Downloaded 385 times (via Modrinth). Download it and open it directly in the game.