Nah, I think Saturn is definitely finished here.
If Saturn isn't getting defeated, Oda wouldn't show his Powers & hype him.
This is his arc, his flashback is tied to Kuma's flashback & we're getting it.
He's like the Imu version of what Vergo was to Doffy or Satori was to Enel.
The first subordinate of Imu that we meet who will be defeated in that arc itself.
I'm saying Power level wise he isn't relevant enough here, it's like place Marco here & he won't be able to move too.
He doesn't matter here. At best he will get some showings & then retreat, at worst he will fully be hypetooled.