The package needs porting to Python 3.13.
There is a PR pending upstream that appears to port away from deprecated distutils.version/LooseVersion, but I'm not qualified to assess its quality.
The comments on that PR also mention that unoconv is being replaced by unoserver (https://github.com/unoconv/unoserver) . The unoconv Github repo has been archived as of March 31st, 2025. Perhaps mark unoconv as unstable or masked now?