Yes, you can use Tracker Import (/api/tracker), explanation in the docs: Tracker - DHIS2 Documentation
You can post back if thereās anything there thatās not clear please!
Yes, you can technically create a Tracker program with zero program stages. If I understand correctly, all the needed data will be in the āenrollmentā (tracked entity attributes)?
My best advice to get the correct API requests, is to create the Tracker program using the Maintenance app while monitoring the request that is sent (using DevTools ā Network) [same goes when filling out the data in the Capture app].
Additionally, like @jason mentioned, it looks like one of the values is not properly set, so check all the ānumericā values.