This doesn't come over night and this is a spectrum and a choice. From purely personal side project over exotic Debian package to friggin httpx with 15k Github stars and 100 million downloads a week the 46th most downloaded PyPI package!
If this shall work reasonably in any way, hou have to step up. Take money (as they do, https://github.com/sponsors/encode), search fellow maintainers or cede involvement - even if only temporarily.
An example of a recent, successful transition is UniGetUI https://github.com/Devolutions/UniGetUI/discussions/4444
I feel there should be support from the ecosystem to help with that. OpenJS Foundation seems doing great: https://openjsf.org/projects. The Python Software Foundation could not only host PyPI but offer assistance for the most important packages.