Hi Cody,
The data set upload through REST API is planned, we will let you know once it's scheduled for a release.
However, we do have functionality that allows importing multiple data sets at a time into multiple data templates. The following article demonstrates this:
https://subject7.atlassian.net/wiki/spaces/SD/pages/467042321/Uploading+Importing+Data+Sets
Regards,
Subject7 Team