[Question] How to properly visualize the model structure as well as save model?

I tried tf.keras.utils.plot_model

But it seems not to work.. only print the model name, is it because we did not use Functional API here?

Also for saving the model, model.save() works but later the weights and summary can not be called even if I do loaded_model(inputs) first.

I am also a little bit confused of Model vs. Layer class. I see all tutorials here use Model class for both query and candidate tower, but -> https://www.tensorflow.org/guide/keras/custom_layers_and_models#the_model_class . It says if you do not need to call fit (which is the case for query and candidate tower), consider use layer class