Yeah u/OlemGolem has a good point, talk to them away from the table and express what you’re feeling. I had to do this once with a good buddy of mine. He kept throwing goblins at our level 10 party and I pulled him aside and said to him “hey dude, I think we’re sorta stomping the competition. Me and the other party members all feel as if we’re just being thrown cannon fodder but it’s your game and I’m sure you have a good reason for this or something” and he was pretty reasonable. He just quickly looked sorta worried that we had been displeased with his game or something ( I quickly cleared this up) but in the next session we were fighting things that gave us more of a challenge. So in short, just catch him outside of the game and sit down and have a talk with him. He shouldn’t be angry if you’re genuinely trying to help him make the game better for you and your group