WTF is up with matchmaking??

Recently I've been having teammates scattered around a large area when it comes to their ELO. I currently have plat 5 mmr, while other players in the game will range anywhere from plat 3 all the way to silver 2 in terms of mmr.

Which makes a huge difference. If my team has a silver 2 ADC, its an automatic loss. If their team has a silver 2 top/mid/adc etc, it is an automatic win in the most crushing, snowbally way possible.

In my most recent game, our team had a duo where one player was silver 2 and their partner was plat 4. I thought that wasn't possible?? Why if there are 3 plat players on the team are there also a gold 5 and a silver 2 player?? The difference in skill/mentality is clearly noticeable. It would be as if I suddenly started playing in low diamond, I would stand out like a sore thumb and lose nearly every matchup.

Can we clean up this matchmaking pls