Doesn't CoreML abstract 90% of the actual model format/training source away? Last time I played with it in Xcode, it was painless to pull a pretrained TF model and use as-is.
https://heartbeat.fritz.ai/whats-new-in-core-ml-3-d108d352e5...
https://developer.android.com/ndk/reference/group/neural-net...
Or you get to use Tensorflow Lite and target both platforms, also with a smaller feature set than its big brother.