In the release group Rembetika: Greek Music from the Underground there are two releases. (They have slightly different release dates but I think that’s just from using different sources - Amazon vs Allmusic.) One has titles and artists in Latin alphabet (as on the physical release) and the other is in Greek, marked as a transliteration of the first. I guess if this were newly created today it would be done as a “pseudo-release”? Should it be converted to one?
From your explanation, it seems so, yes.
I have changed the status and removed the label / release events. https://musicbrainz.org/edit/55358163
Anything else that should be changed? It already had the ‘transliterated version of’ relationship.
I have changed the only Latin artist credit to Greek.
You should also remove the cover art and medium formats. Also, you might consider transliterating the release title and “Various Artists”.