So I've been working a lot recently on trying to understand more advanced harmony and chord progressions but this one has me stumped as to why it works/sounds good. The way I hear it, it goes like this..

Bbm7 -> B7 -> D/C -> E/D -> Gmaj7 -> diminished descending thing, then it restarts the progression.

Love this song and progression. It sounds so cool but I can't make any sense of why it works, and I have kind of an obsession with trying to figure out the "why" something works. Is there any logic to this progression someone can explain to me? The best I can come up with is that it is a "modal" progression where each chord almost acts as its own key, but then again idk what I'm really talking about.

Anyone have the answers?