How matchmaking of ranked solo/duo actually works>>>

Matchmaking will always try to put you into even or close to even games based on mmr (hidden number that you can't see) that doesn't need to be same as their current rank. The biggest probem is that players never play their best every game, so games feels unbalanced, but it's because of players, not because of system, also players menthality also matters, toxic players and player that give up early will lose more games just because they lower team moral, other team members might not try their best aswell since their attention will not be on game, but on chat. Also ranked solo/duo have currently most even matchmaking, other modes usually put you in uneven games with big skill gaps.