I agree with you and I myself have been struggling with that for a long time. I've reported Riot twice about the matchmaking and they simply said it's all about luck and they're sorry I'm getting bad players on my team.
You can go to your.gg - They literally describe your matchmaking luck on 5 scale, mine is on the "Worst" scale right now but I'm getting better at winning these games despite the matchmaking conditions. I've seen your profile as well and your matchmaking luck says "Worse" as well. Nothing can be done about it.
Trust me - I'm a literal and a very bad type of flamer and I've been chat banned twice for flaming and trust me, sometimes even I'm surprised why Riot doesn't permaban me for my 200% toxic behavior.
I went to your.gg and saw my stat, I understood that I really am getting bad players in my team and there's nothing I can do about it but suck it up and climb through it.
Sometimes I feel Riot is intentionally doing this because I was chat banned twice. If you've been banned before, let me know, maybe that really is the reason the matchmaking is worse.
Eventually I found a pair of champs which could hard carry through alot of things and you can check my op.gg right now and see how hard I'm trying to carry my teammates to top, having max damage and Kill participation in almost every match.
Eventually after 2 weeks of hardships and crying and grinding, I've managed to equalize my winrate from 46% to 50% (79W 76L) and I'm currently getting 18-19+ LP for each win and losing 20 LP for each loss. Even beside that, I've managed to make up a mentality that every game I'm going to play, I'm gonna get a bad set of Bot lane and a bad mid laner and I'll only have to play Top lane and rely mildly upon jungler to win this game ( Trust me, junglers really are the backbone of every match and 90% of the junglers out there are pretty good players if given optimal conditions for ganks).
Bottomline is - Start playing meta junglers, maybe Shyvanna since you have 80% WR on her. But trust me, no matter how sweet and caring Riot Support portrays itself to be, I do know something is fishy about matchmaking and they are heavily trying to demote and promote people in elo because of unknown factors - Maybe RP advantages or something. G'Luck.
