Help changing the biome of a coordinate through a procedure?

Hey there, I'm trying to make a biome that 'spreads' similar to TC4 taint, by having a catalyst block creep outward and changing the biome as it does so. However, there appears to be no procedure blocks for changing the biome (despite there being ones for checking the biome of a given coordinate), and throughout multiple java docs with a couple hours of digging, I was unable to find any way to get or set the biome at a specific coordinate through code. I fully believe that there is no way to set the biome through procedure blocks, but if anyone knows how to set the biome of a coordinate through code, I'd be very appreciative.

Side question: How do you even acquire a net.minecraft.world.chunk.Chunk class object? Most of the aforementioned hours were me trying to find any sort of way to get a chunk's biomeArray, but that cannot be gotten from an IChunk (The chunk class type you can get from an IWorld, which is known as 'world' in procedure dependencies), only a Chunk - at least from what I know. And every method I could possibly find (for Worlds, IWorlds, MinecraftServers, various events, etc.) would only give IChunks.

Every biome change topic I could find on this forum has been abandoned before they ever got answered. Every potential source I've found is outdated. I'm genuinely going mad over this. Please help.