But some are worth the extra time.
The Best of Youth is 6 hours and is incredible-- you just have to break it up over a a few viewings unless you have a ton of time on your hands and don't mind sitting that long. But it's worth the time.
Snyder's Justice League at 4 hours, on the other hand, is a waste of time.
Killers of the Flower Moon was about 3.5 hours, and could have been shortened IMO.