That's not a bad idea. Although, the franchise has mostly worked with claustrophobic spaces. The open spaces are mostly massively inhospitable, forcing the characters to stay indoors (Fury 161, LV-426). Prometheus and Covenant had moments where the characters were out in the open, but they usually ended up back in those dark, claustrophobic spaces when the monsters attacked.
Mad Max-style post-apocalyptic settings are literally the opposite of the franchise's natural setting. That could be a good thing, undoubtedly. It would be harder to maintain the tone or vibes people would expect, however. Wide open spaces are exhilarating, but not usually scary. Though Ripley as a gnarled Mad Max figure would be super cool. If characters end up the ruins of cities, you could have them infested with aliens. Out in the desert, it would be harder to create the thrills, as the aliens would be out in the open. Maybe they could swim through the sand and leap out? I'm not sure on that one.
However, a zombie movie tone could work within that wider, more expansive setting. Humans trying to hole up in a building/town/makeshift fortress under siege by xenomorphs, for instance. Perhaps if the world outside is a wasteland, it keeps them from running because there's literally nowhere to run to--except an endless, blistering desert. They have to stay and drive the aliens away to protect, say, their generator or well. But then someone inside the town/fort/whatever lets the aliens in... (Treachery tends to be a second-act trope in the Alien films: Ash, Burke, Golic (in AC only), Wren.)
Or you could start with the outpost under attack from the aliens, so the townspeople have to flee, crossing the desert to find a fabled research station with its own water purifiers and hydroponic gardens. Of course, when they get there, the aliens have already taken over, so they have to drive them out and fortify the place for themselves.
