You might want to print out the properties in the tilesets:
https://cesiumjs.org/Cesium/Build/Documentation/Cesium3DTileset.html?classFilter=Cesium3d#properties
Given a tile: https://cesiumjs.org/Cesium/Build/Documentation/Cesium3DTile.html
You can get tile.content and then featuresLength:
https://cesiumjs.org/Cesium/Build/Documentation/Cesium3DTileContent.html#featuresLength
If that’s 0, then the tileset wasn’t created with the features you need. This example might be helpful too:
You could also try tiling the data with cesium.com/ion just to check if the issue is in your data or in the tiling.