Matchmaking suggestion

If you have been purple for 5 solo games in a row, your next solo game will place you on blue side. If a match is found and no combination of players can put you on blue side, the game skips that "boat" and waits for the next possible matchup. (Though, it is difficult to believe that no combination of players could put you blue; your MMR would have to be worth enough to put you purple even if the next top 5 MMRs were all played against you.)

You should have the option to turn this off in the settings if you don't want to wait extra. Obviously doesn't work for duo.