The mod generates oak by default, has an optional datapack for acacia which I assume is because Ilmango went acacia, but what about the other trees. What if someone wants to do birch or spruce for example, effectively the same difficulty as acacia, but allows for a different wood texture and acacia also has that weird generation that some people hate chopping down. As a workaround is there something that can be changed in the optional acacia datapack to get a different tree type?

I don't really want to embed a bunch of different datapacks for each tree type because it will just add bloat to the datapack selection screen.

If you don't want to just switch into creative and swap the tree out, you can create a datapack that overrides data/carpetskyadditions/structures/spawn_platform.nbt with a structure file of the spawn platform. You can create the structure file using structure blocks.

Here's a zip file of birch, spruce, dark oak, and jungle tree start structure files

spawn_platform_structure_files.zip