Matchmaking in blind pick normals is kinda messed up

I play league as a hobby and I love the game. But I'm someone who plays blind pick normals more than ranked. I've clocked in almost 6,000 normal blind pick games and only 60 or so ranked games (this season). I like the uncertainty of the matchups and the variety of team comps in blind picks.

But lately, I've been having some serious matchmaking issues. I get silver, low-gold teammates while the enemy team is full of plats and diamonds. Ok, I must admit, I'm only G4 this season, but that's cause I barely play ranked. I play mid/jg and I can hold my own against higher elo players. But, the same can't be same with the people I'm paired with. I'm not gonna flame on my silver/gold teammates. I can't expect them to be as good as plats and diamonds. It's not just about macro-play and game understanding, their mechanics are also not on par. When I check on lolnexus or op.gg and I see that my ADC or mid is silver and the enemy mid or adc is diamond 2, I just know it's gonna be hard.

But then, when I go on ranked and play ranekd games, I feel like the teams are so much more balanced. I feel like my ranked games are so much easier to win, cause the two teams have equal-skill leveled players. In normal games, sometimes I'll have 0/8/0 mid-laners pre-10 mins. But that's cause he's silver 4 and his lane opponent is a diamond 3 or sth. I won't blame him and I never say bad stuff to my them. But I feel like that shouldn't be happening in the first place. Maybe it's because I have a lot of games under my belt (again- 6,000) but I feel like matchmaking thinks I'm way better than I actually am.