I might be missing something here, but it sounds like all you need to do is edit the playlist settings and tick "custom fields for this playlist only"
that will also enable the sorting to remain local to the playlist in question
That was already ticked.
I just don't really get the process for the sorting for that specific playlist.
If i do "sort by sort album" on that one playlist, it changes the setting for every playlist. If I create a Custom View when i got it set to "manual order", then select it, it doesn't change antyhing. It doesn't work the other way around too, tried to create the Custom View setting, and only sort to "Sort Album" after, it doesn't change anything at all either. It all just seems like it's ignoring everything and just goes with the default "sort by" general value.
Btw i've got my view setting set to "Album Cover" for all playlists. Idk if that changes anything