I add mods and they keep adding new slots to the baubles tab. I have 8 ring slots and only want 4, as well as 8 charms and only want 3. I cannot figure out how to change this. How can i?

This would only occur if the mods are purposefully adding more slots. Which mods are causing this behavior?
As a last resort, you can override the behavior yourself by using the curios-server.toml file as outlined here:
https://github.com/TheIllusiveC4/Curios/wiki/How-to-Use:-Users

Something like:

[[curiosSettings]]
  identifier = "ring"
  size = 4
  override = true

I added the override command onto the end and it worked as soon as I put it in. Sorry about that, and thanks for your help!

for the record, it turns out cyclic appears to intentionally request a large number of slots.

i started to comment on this as a "i also am experiencing this problem", but i dug deeper and... yes. it appears to be intentional.

https://github.com/Lothrazar/Cyclic/blob/trunk/1.18/src/main/java/com/lothrazar/cyclic/compat/curios/CuriosRegistry.java#L23-L33

bewildering, but clearly intentional.