Sphinx and xindy

I have been working on an update for coq 8.9.0 in Rawhide. A mock
build fails when building the documentation:

Latexmk: applying rule 'makeindex CoqRefMan.idx'...

The dependency on xindy comes from Sphinx. Take a look at
%{python3_sitelib}/sphinx/texinputs/latexmkrc_t, which is used to
create the latexmkrc for coq that refers to xindy.

As I understand it from looking through bugzilla, the texlive-xindy
package was dropped because it frequently failed to build.

So what is the right thing to do here? Try to debug the xindy
problems so the texlive-xindy package can be resurrected? Disable
xindy support in python-sphinx (if possible)?