If you're going to make The Green Knight, do that. If not, don't base the film off one of the oldest and most well known stories in existence. People leaving these pretentious 5 star reviews are outing themselves for having 0 reading comprehension -- this movie shouldn't have bothered to market itself as the tale of Sir Gawain specifically if it didn't want backlash for failing the character so spectacularly.
On another note, if a movie is going to spend a good 65% of the film in lighting so dark the screen is just black, cut the scene. Movies that can't afford CGI or SFX need to stop thinking people are somehow fooled by a bad lighting job. It especially took away from a film that seemed to pride itself on its visuals.
Anyways, save yourself the trouble. If you want a deep film that ACTUALLY has a plot and character development watch Patel's "The Lion". It bothered to be interesting.