Here in PVJWorldGenEvents.java you add Vanilla placed features to vanilla and other modded biomes. This can cause a feature order cycle error when playing with mods that add other biomes.

A fix for this that should prevent the crashing alongside other mods would be to duplicate those placed features but register them as your own in PVJPlacements.java.

This should prevent this crash from happening alongside mods with biomes.
java.lang.IllegalStateException: Feature order cycle found, involved biomes: [Reference{ResourceKey[minecraft:worldgen/biome / minecraft:river]=net.minecraft.world.level.biome.Biome@5b2258ac

Thanks for letting me know, should have a fix out soon.