I just filed this as FB13809430 but the text for Google search archaeologists looking for a fix this has worked for me—with a MAJOR caveat for those on shared networks—is as below. I hope this helps with someone's frustration.
I see this on Apple Support forums, e.g. Home sharing still broken - Apple Community and 13.0.1 Home Sharing not logging in - Apple Community so presume there is a reason this has no attention. But I am dealing with it (not relevant but a restore needing a lot of file sharing and copying). Don’t know when it was introduced but definitely there in 14.5 (23F79).
Previously, Home Sharing was toggled from within Music & TV (and their predecessors). Now, it is in System Settings/General/Media Sharing. Through trial and error I have found that:
1. On the same wifi network logged in on the same Apple ID, this only works if “Share Media with Guests” is enabled.
2. Note initially selection needs to take place in grayed out fields, as pictured. They are actually clickable; this is a UI bug.
3. You cannot just de-select all playlists—only active playlists, or alternatively all, will enable the feature.
This is (I think) not a security hole, but *IS* a privacy hole!