Unlock Both Endings in DREDGE
Yes, you can get both endings on one save file. In DREDGE, you turn in the five Relics (main-story keepsakes) to The Collector at Blackstone Isle. When you reach the ending phase, the game keeps a save right before the final lock-in (the point where your choice is locked), so you can finish one ending and then go back for the other.
Ending 1: Unshackled (default)
Requirements: Deliver all five Relics, tell The Collector you are ready, then sail to the marked spot west of Greater Marrow. Interact there to follow the ritual route and earn Unshackled.
Ending 2: Sated (alternate)
Requirements: Find the Old Mayor at one of the abandoned campsite docks (makeshift docks), then talk to the Lighthouse Keeper in Greater Marrow about the silver-and-crimson book. Confront The Collector and keep pushing that dialogue path until you take the book. Return to the Lighthouse Keeper, then go to the marked ocean location and choose "Throw it back" to lock in Sated.
Fastest path for both: do Unshackled first, then continue or reload and run Old Mayor -> Lighthouse Keeper -> take-the-book route for Sated.