There's a set of utilities[1] in a package called patchutils that contains several commands to manipulate patches. Their version of splitdiff[2] will create a set of patch files from a single patch where each patch would only apply to a single file. It doesn't appear to have the capability of splitting out individual hunks like your version, but could be updated to do so.

[1] https://directory.fsf.org/wiki/Patchutils

[2] https://www.unix.com/man-page/suse/1/splitdiff/