Okay look, this is something you people will not like hearing but you need to. So prepare yourselves.
- If you premade, MMR is boosted because it assumes that the improved coordination adds to skill, which is a completely fair assumption for MMR calculations.
- People that are Diamond/Plat, don't have very high normal MMR becausethey don't play a lot of normals. Normal and Ranked MMR are separate, for as long as this is true, you are bound to encounter some of them some time in normals.
- Unless there is a huge level discrepancy (i.e. 8-10 Level difference across all players), it isn't unfair. You won enough to have your premade MMR that level. This is who you are matched against.
If you want to full premade and have fun, then have some fucking fun. What exactly is the enemy premade doing that is preventing you from having fun? Winning? Beating you? Spoiler alert - Winning is fun.
Guess what, I premade with friends too. When we premade and are getting owned, we laugh. Carry just got bursted so fast we didn't even have time to blink? Let's swap, carries go tank and tanks build carry! Somebody got caught? Maybe we should bring them fishing cause they seem to make good bait. We don't go out of our way to make our friends feel bad or tell them they suck or complain about enemy skill. You want to have fun? Have fun, do whatever the fuck you want. Make jokes, come up with a plan and try it.
If you only complain about facing better opponents; if you are going to bitch and whine when you actually have to play decently to win because your opponents aren't incompetent; you are weak-willed and spoiled. No one is getting in the way of you having fun except you. You want easy wins? Go play a damn coop. You want to play against other players? Learn how to have fun regardless of win or loss because in case you haven't fucking realized, nobody wins all the damn time. Knowing how to take a loss is part of being a good sport.