Finally watched the whole thing after spoiling myself on plot synopses and seeing TikTok excerpts, and it actually does hold up better when seen as an integrated whole.
It has weaknesses in hindsight, most notably that Peele has to force his final climax into the shape he wants by making one character (the film's sole significant Caucasian character, more notably) do something utterly, stupidly nuts without sufficiently foreshadowing it; this would be forgivable if it didn't resonate with the thematic thread running through both of Peele's previous films, which says, "Hey, black people? Don't ever trust white people or count on 'em, they'll let you down or eff you up; they crazy!" It also suffers, I think, from the fact that it can't really decide whether its primary thematic inspiration is Tremors or Jaws; it wants to have the comic overtones and science-fiction slant of the former but the small cast and intimate intensity of the latter, and feels uncomfortably caught between them. But it has enough spectacle (no pun intended) that I'd call it worth seeing all the same.