Feedback about Ranked (low elo)

As a player coming from HOTS in which i was Gold1/Plat5, I switched to LoL one year ago. I managed to get a bunch of champions Lv7 to play ranked properly and get used to the game slowly. I want to give a feedback about ranked system this season.

In my last 20 games in ranked based on OP.GG stats (link available in my post) : 7 times I was MVP (winning team) 7 times I was ACE (losing team) I can understand RIOT saying it proves their matchmaking system to be working as they intended because I end up basically 10 wins/10 loses. BUT as a player, I think there is a problem being best player of my team 14th times in 20 games AND STILL being stuck in Bronze 1 as soon as I have more than 50LP. It becomes very boring. When I reach Bronze1 with more than 50LP the game feeds me NON-STOP with teammates I can't win a game with. My sensation is I am just feeding the machine and I can't climb the ladder to play with better players.

How comes I get an ADC Bronze3 using Vayne with 400points in ranked? How comes I get an ADC Bronze3 using Kaisa who manages to die 18times? Is it ranked or super draft mode? IS RIOT doing enough to make understand what is supposed to be Ranked mode?

My suggestion : From Iron to Silver RIOT should forbid the use of champion below level3 experience.