Choose which accounts get mixes.
On a server with more than one person, the plugin built a full set of playlists for every account, whether or not anyone there wanted them. There is now a field for it in the settings, under Playlists:
Build mixes only for these accounts takes a comma separated list of usernames. Leave it empty and everyone gets mixes, exactly as before, so nothing changes for an install that does not touch it. Fill it in and the accounts you leave out get no playlists at all.
The saving is not only tidiness. A run spends roughly 300 Subsonic calls per account: one getStarred2, two getAlbumList2, 200 individual getAlbum calls, and four or five more for each of the twenty or so playlists it writes. The check happens before that work, and before the command mailbox poll, so a skipped account costs nothing. And an account that never asked for this stops finding twenty playlists in their own library.
Names are matched ignoring case, and a skipped account is logged once per run, because a setting that quietly stops the plugin doing anything is the kind people have to guess at.
Play history is still collected for every account, on purpose. Collecting costs one small key-value write per play, while generating is the expensive half, and it means an account you add to the list later starts with real listening evidence instead of warming up for weeks.
What this cannot change: Navidrome shows an admin every playlist on the server, including other people's private ones. That is Navidrome's own visibility rule. Narrowing this list is what shortens an admin's playlist page.