Clarification with Duo rules

I'm not really upset or anything, but I'd heard something that gives me a conflict of interests. In solo/duo queue ranked, I'd heard from my friend that queuing as a duo matches you against better players. I wasn't sure about that, but recently its become clear that in over half of the games we play together, our teams get absolutely outmatched despite us powering through bottom lane pretty much (though not every) game. These mismatches in skill mean that more often than not, we're losing in really unsatisfactory ways and it's grinding on our mental. Alternatively, when I queue in solo, because I'm a Varus 1trick essentially, I win most games with a winrate hovoring around 60% with him in solo, and my teams feel much more comparable in skill to the enemy. It's getting to the point where I have to choose between having fun with my boy and understanding we're probably in to lose some LP, or queue alone, have a probable net gain, but have less fun playing. Before I just accept this reality though, I figured I'd ask if anyone had any light to shed; if there really are matchmaking rules in place that dissuade duos or incentivizes queuing solo. Maybe there isn't, my friend was wrong, and we just have really shitty luck. I just want to hit platnum with my boy.