Suggest me a movie where acting alone worth the watch

I just randomly watch "Elvire Jouvet 40", a french movie that re-act theatre lesson from an old famous dramaturge Louis Jouvet.

I didn't understand much because I mostly watch casual or mainstream movies but the acting was so good that i watch the entire thing anyway

Do you know more movie like that ? I don't specificly want niche movies, movies where everyone play good or Oscar material movies but an incredible leading role prestation that alone worth the watch even if the movie is mild