The Gunk - made by the Steamworld developers.

Ok yeah this is a very B game, but as Game Pass filler it’s fine. It’s super indie in the story, it’s a couple working through relationship issues over an alien disaster that’s a climate change metaphor. Around 4 hours or so to beat it, fairly linear and very little challenge in either the combat or puzzles. A game doesn’t need to be challenging to have engaging gameplay, see Unpacking which is not remotely challenging but is engaging. I think the core problem is dealing with the Gunk is never very interesting and mostly feels like busy work. Also despite being linear they do manage to have a level with poor signposting that is kind of annoying near the end.