If the dev cycle feels slow in julia, you can make it snappier with a tool like Revise.jl, it is quite handy.
If you just need to fill a small and slow gap maybe something like numba is also a good option to stay within python.
Going all the way to a low level language would require the compilation, the glue code and expertise in both languages. Probably that slows down the development pipeline more than the JIT compilation from julia or numba.
Anyway, any opportunity to learn/practice some rust is also great!