Need to generate dimension with 2D biome noise map but can only use 3D multi-noise

My biomes aren't generating properly, some are almost never generating, and too small when they do generate. I realised they are generating high up in the sky above other biomes or underground below other biomes. This should not happen, and results in biomes not being visible and not producing any features. This is an Overworld type dimension and I am not using Depth in any of the biomes, I want them to generate as a 2D noise map as in legacy Minecraft. MCreator 2025.2 does not support this, and even after locking the code and manually editing "multi_noise" in the biome generator to "noise" it crashes the game when clicking "Create New World". I fear Minecraft 1.21.1 may not support 2D biome noise maps anymore. How do I fix this?