Congratulations to last.fm on this, although I'm not sure what I can do that actually "scrobbles" at this point. I went to their download page for the Mac desktop app, which somewhat forebodingly referred to "what you've been playing in iTunes" rather than Apple Music, and downloaded it anyway. It's an Intel-only app, not universal, and it doesn't appear to be signed, so macOS Tahoe screams about it being possible malware.

After going through the hula dance to open it anyway, it looks like it's working, but it sure doesn't look like it's received a lot of love recently.