Spoilers ahead, don’t read this if you haven’t seen the movie

Brynn lives in an isolated house so she’s one of the last people to get infected. The aliens even leave c-shaped prints in the yards of the houses they’ve visited.

The aliens spit covid-like parasites into your mouth to make you one of them. The parasite even lodges in your throat.

Gray aliens themselves have kind of an Asian appearance and might be some sort of relic from the (ongoing) yellow peril. This comes from the idea that the Chinese created covid to destroy America.

At the film’s end, everyone is infected with covid but pretending to be okay.

Am I crazy here or actually on to something?

I thought this explanation was also pretty good (https://collider.com/no-one-will-save-you-ending-explained/) but no one else seems to think the movie is about covid.