I have a regular SDK project so I can edit the assets and then just manually call ./gradlew run from the command line for gradle, but you could also use two IDEs then, the SDK for Model Editing and One for Gradle, possibly you could also just use two projects and copy the files back and forth.
I looked into the issue last year but I couldn’t get to even depend on the gradle plugin when creating a new SDK Module to the point where the Netbeans Guys were clueless as well…