Yes, I know, it's been mentioned a thousand times. I did check the FAQ, the Curse dependencies, and all previous issues, but I can't seem to find a mention for which version of Baubles is matched with the current version of Botania - everything I found is a month or three out of date. Is there any way you could mention that somewhere?

Just get the latest Baubles version for your minecraft version. It should work unless there are API changes on baubles side.

Tried that, got the usual error. Both 1.3.8 and 1.3.BETA11, on the off chance the older beta worked.

just use Baubles-1.10.2-1.3.6
It's what I've been using and if there's issues, post logs.

The code says required-after:Baubles@[1.3.BETA8,]. Does 1.3.BETA8 work?

The dpeendency string probably should be updated