We talked a little bit about this in #25993 but didn't resolve things.

Currently, the following functions don't have implementations in np.strings:

We should figure out the appropriate API for adding fast ufuncs for these. I'm actually not sure if it's possible to write ufuncs for these given that they have an unknown number of outputs for each array element, you really need ragged arrays for this to make sense. Although that said, we could also return object arrays of python lists or just leave them with the _vec_string implementation.