It's not surprising then that The Green Knight would be a polarizing film of differing expectations.
Maybe they were expecting something more conventional, which is a mistake considering it's written and directed by David Lowery, who has dabbled in a studio sphere (Pete's Dragon, the upcoming Disney Peter Pan remake) but seems more at home with introspective, quiet, occasionally overly obtuse art-house pictures, the kind like 2016's A Ghost Story where Rooney Mara eats a pie for ten minutes (I will never forget this puzzling movie moment). Much like the contentious differences of opinion over It Comes at Night and Hereditary, it seems like general audiences are a little more indifferent to hostile for this arty release than the critics.
The Green Knight is an indie drama heavy on atmosphere and mood and a little lax on pacing, falling into yet another A24 discrepancy between critics and audiences.