There is work in progress to expand the backend rules engine in 2.35, and trigger program rules by “pinging” the event with a PUT or POST request.
See this CoP post with explanation: Backend program rules - #2 by jomutsani
And this JIRA ticket: DHIS2-7310 - Expand backend rules engine functionality: Assigning, errors and warnings
Currently the only PR Action available to trigger through this method is the SCHEDULEMESSAGE or SENDMESSAGE for SMS Program Notifications.
Maybe @Markus and @dhis2-tracker team could address this?