Randomize object placement in Unreal Engine so every frame is a different arrangement and the labels follow automatically. The rules worth having, the three artefacts a naive random scatter leaves in your training data, and what re-placing everything between frames costs you.
https://dev.epicgames.com/community/learning/tutorials/yJDB/how-to-randomize-object-placement-in-unreal-engine-for-synthetic-data-generation