Im currently playing on a sealed world and found out that alex caves biomes dont spawn. I tried adding chunkbychunk:skychunkgeneration after seeing an earlier post have a similar issue to the alex caves config but it didnt work in my test world of the same seed. Is there another id for sealed worlds in regards to generation?

mmm, it should be chunkbychunk:skychunkgeneration for normal and unstable chunk spawners, and then each themed chunk spawner has its own dimension - but then those wouldn't include Alex Caves biomes without other work as well.