as the code works on Linux I can think of two possibilities:
- Due to limitations of the native Android and iOS platform, certain 3D features / objects / textures / formats might not be supported on mobiles.
- There’s a Qt bug which only affects mobile platforms.
Maybe also some code changes are required to make some features work on mobiles. I suggest to make sure that your code is correct and that you can run 3D on mobiles, e.g. with some of the Qt 3D examples.
For further help about Qt 3D, I recommend to ask in the official Qt forums.