I have a custom structure datapack, it's really simple, and i'd like it to generate as the chunks fill in through the chunk spawners, however it seems to override it. what changes should i make to a pack that works in vanilla to make it work with chunk by chunk?

Um, not sure... Potentially the way I'm setting up the generation dimensions isn't compatible with custom structure datapacks, if they're tied to the overworld. I would have to experiment and work out what is happening - but unfortunately I'm not currently maintaining this mod (working on other projects) so I'm not sure when I'll have a chance to investigate.