It's set on an Earthlike planet that later turns out to actually be Earth. The main thing I can remember is the main character encounters some sort of 4-legged walking drone that we assume is alien but it turns its head and reveals a Union Jack on it and is clearly a military drone.
The story has a big reveal in it where we go into some military base and learn the planet has pretty much self-destructed because a space ship appeared in the sky one day... which turns out to be us... and then it turns out this is Earth and we caused our own destruction.
I think it was one of those movies that went straight to Netflix or Amazon and has about four cast members in it at most.
