FWIW I was able to import a CSV datatype that was linking to an option set. It was a few months ago so I don’t recall the exact process, but I seem to recall a few things:

  1. Option set has to already be created in Bubble. It needs to contain every single option that the CSV uses in whatever column you’re linking to the option set.
  2. Setting up the link so that the CSV column that is the option set knows which field to look for in the Bubble option set to establish the link.
  3. If Bubble is uploading and hits an instance where a CSV thing’s option is not in the option set in Bubble, then the upload (or maybe it’s the pre-upload check) stops.