Solo queue > enemy is also solo queue > win.
Solo queue > enemy is a team of 4/5 and coordinated > loss.
Solo queue > your team has a duo+ > 80% chance of 4/5 man enemy team > loss.
I win 65% of the games that I play where everyone in the match is solo. I win maybe 10% of the games where the enemy team has a 4/5 member team. I also run into teams of 4/5 as a solo queue approximately 50% of my matches.
Solo queue only, I am able to rank. However due to teams of 4/5 enemy players are in 50% of my games, I find it quite literally impossible to climb. What makes it worse is teams of 4/5 only one a 1/10 or a 0/10 chance to get a troll or a griefer on their team while I have a 4/10 chance every single game.
Ranked is impossible to gain points unless you team with 4/5 people to increase the odds the enemy team gets bad players who troll or are just bad.
tldr; ranked solo is like gambling with much worse odds than a Vegas casino.