Men with crazy fast metabolism in your 20s do you see a slow down in your 30s?

Very hard to gain weight despite eating at a surplus. I can't physically find time ot eat more doing everything I can (creatine, milk shakes) and all the little hacks youtubers that gains a ton of weight give. My only way to gain weight (muscle) is to slow down my metabolism. Has that happened to you? Eating same calories at 20 and at 30 starting to gain weight/get stronger.