If Sinners and One Battle After Another are up for movie of the year then it's no wonder no one is going. One is a fun but ultimately forgettable horror action movie. The other is a movie that just based on its major theme would attract less then half the country and even in those remaining is a very polarizing movie. It's up for best picture because to preach, not because it's actually good.
The obvious political stance of One Battle After Another notwithstanding, given how much the film succeeds as an exercise in using the language of cinema to tell a compelling story, it comes across (ironically) as idealogically motivated to say the movie isnt nominated in part for its merits with regard to craft and construction.
No doubt it appeals to people at the Academy in its persuasion, but if we were to strip it down to film technical aspects it would no doubt still be a frontrunner for film of the year.