Really good. Reminds me of another story, The Quiet Sky or whatever. Same tone, same scope, and totally hopeless. That part "it doesn't need us" sounds edgy but it's so stupid. It is clearly eating people and making more of it from the remnants of our civilization. If anything, it's one of those answers to the Fermi Paradox. Like those moons from Dead Space.
Funny, you can imagine this story as a prequel to the Dogscape, the flesh effectively consuming the planet for the remaining nutrients it needs to one day fly off into the cosmos. Whatever humans remain on the surface, consuming the meat and drinking the blood and sweat of this thing like overgrown fleas, simultaneously worshipping and fearing the flesh both as collective trauma and a realization that without it humans would be no more.
Maybe they manage to survive even after it leaves, and after many long generations their numbers expand and they learn to control and dominate the flesh in an ironic twist of fate. Civilization expands, and like a phoenix it blossoms into something far greater than anything we could even dream of had that Cloud never arrived... not really sure where I'm going with this, but it's a comforting thought. If I was there it'd probably be the only reason I'd keep living after all that. That, and pure spite.