Matchmaking is not that terrible at least in my elo, if matchmaking seems so weird to you consider the fact that you are playing heroes you are not too good at cause the system does not consider heroes you play much. So if you main tracer and do well the moment you change to play Sombra you will be matched with players of your tracer level and playing a different hero it will appear as if other players are much better or a lot worse than you are. Its just comes with the territory of a game like this. Or playing at really off peak times in your region will get you games with very diverse players like if i decide to play at 4am in my EU region.
im sure you have come across this at some point:-