Me and my friends Go-To dream games always starts with two words Free-Roam, so I thought i was funny that you started with that cause its a good answer that I relate too.
But anyway that's cool, Personally I think when Shamash is defeated and Uras-Beherit is either Captured in a time-loop, imprisoned or repelled, Harec and the gang will probably use the Legacy to either go back in time and Prevent the initial accident or find a way to connect to the Aleph core and repair the planet that way.
If they go to a new planet without Aleph idk what the Raiders will be Raiding exactly as the Aleph is the center piece of this game. I also have a hunch that like Uras-Beherit the Aleph is also alive.