Hi.
This release has been entered with the title “I grandi successi originali”:
If you look at the cover, on the upper right corner you can read “Flashback” and on the CD spine there is only “Flashback - Oliver Onions - 74321797222 (2)”.
On both CDs there’s also no mention of “I grandi successi originali” - instead there’s only “Flashback”.
“I grandi successi originali” appears to be a series name, and “Flashback” appears to be an imprint of the RCA Italiana record label. There is a long list of albums with those emblems for many different artists.
Discogs seems really inconsistent on this, but there is some corroboration:
Musicbrainz has a series called “I Grandi Successi Originali,” but it also has that as the album title for most (but not all) of the albums.
It sounds like this is a question that needs an authoritative decision followed by some clean-up. If it were me, I would say:
Album title: Simply the artist’s name
Series: “I grandi successi originali”
Label: “RCA Italiana” and “Flashback” (and possibly “BMG,” if it’s on the back cover)
Both ‘I grandi successi originali’ and ‘Flashback’ are series. In many cases they will overlap on the same releases (see the release posted above, or https://www.discogs.com/release/10977326 for a later example), but on some releases only one of the two (usually Flashback) will apply. I do acknowledge that the distinction between sublabel and series can sometimes be blurry, but the rationale is that Flashback is not a separate (sub)entity with its own discographic history.
Release title: no strong view. For the 2000-2004 releases, ‘I grandi successi originali’ seems a lot more prominent on the front cover than ‘Flashback’, which is probably why that became the natural choice for many editors. For the 2009 releases, both seem equally prominent.
The label should be determined on a case by case basis, based on https://musicbrainz.org/doc/How_to_Identify_Labels and following the usual MB practices (i.e. not listing every single entity, but only the relevant one(s)). As per the annotation over at https://musicbrainz.org/series/34f3e11e-dfa4-43f1-b094-6228d5f0af4c, releases in this series usually carry the Ricordi, RCA or RCA Italiana imprints. I don’t know where ‘Sony Italia’ comes from, but please please don’t use that.