Please don't type if it's "lol you're bad"
I mean, what are you expecting? You arent consistent in your game, yet you claim its matchmaking. You already played 39 different champs, I dont want to question your decisions, but thats just quick way to tank your mmr.
I dont want to call you liar, but I have doubts about this "I was P1 with D3 MMR on EUW", but then again, so were I and 7% of community(now its like 2%?).
I personally managed to drag this acc, with G4 mmr while being G2 back to dia and I aint stoppin there.
I dont feel big difference in low-mid eune elo compared to euw(I would say you can rely on EUW team mates little bit more), I suspect it changes heavily from D1+.
If I came out as angry or shamer, I didnt mean it in that way, but it just doesnt look like you are the main carry in every single game yet you claim that your team is dragging you down.