I'm disappointed that Google shut down the Swift for Tensorflow project, because I do think Swift is a great option for deep learning.
In some ways Jax is almost "non-python deep learning" since it's treating Python more like a DSL for the XLA backend. Normal Python code doesn't work in Jax. It's a pretty reasonable compromise since you still get all the benefits of the Python ecosystem.
Julia seems like it has the best foundations for deep learning, since everything can be written directly in Julia. But it doesn't have a great ecosystem as a general programming tool.
In some ways Jax is almost "non-python deep learning" since it's treating Python more like a DSL for the XLA backend. Normal Python code doesn't work in Jax. It's a pretty reasonable compromise since you still get all the benefits of the Python ecosystem.
Julia seems like it has the best foundations for deep learning, since everything can be written directly in Julia. But it doesn't have a great ecosystem as a general programming tool.
F# might turn out to be a good option.