> Implement their methods from scratch (i.e. numpy not pytorch)

lol this is basically impossible and completely pointless. please show me a numpy implementation of BERT or CycleGAN or deformable convolutions (note that jax != numpy). it's like suggesting implementing a kernel to someone who wants to learn about virtual memory or scheduling.

better advice would be take a paper and implement the model using pytorch without looking at their implementation and fiddle with that.