So from what i have been able to see is that it seems to be an account connected thing.
My first account, which I started using for playing OW2 since season 1 (0), seems to be cursed/flagged/hated by blizz since I seem to end up with mostly bad teams against what seems to be teams from either higher division and/or just better skilled.
61 games won as support, managed to get to Silver 3 and now went down to Silver 5 due to bad team mates. Either not being in voice, not communicating at all or just overall being bad.
When I got a feeling something must be wrong with my MMR or something I made a new account in season 2 where I was placed in Silver 4 after the placement games.
When Season 3 began, my main account, where I had many games/time invested i ended up being deranked to Bronze 3 after finishing Season 2 on Silver 3.
My second account, which placed Silver 3 as well, was placed at Silver 4 for the beginning of Season 3.
I already thought this was weird but didnt give much thought to it and continued playing my main account for 55 more wins in which I went up to S3 and back down to S5 after almost only losing games.
So I went back to my second account, made 15(!) wins and am now on Gold 4.
I am playing the same role, Support, playing the same champs, seeing the same numbers in statistics (dmg inflicted/healing done/deaths) and yet, on my second account I am being placed in way more balanced teams leading to me being able to actually SUPPORT my team mates rather then seeing them inting like mad men.
The whole system is faulty and it is not even related to luck because I can actually see and feel that whilst I am playing the same way, both accounts have a different game experience in comp.
Quick play seems to be the same on both accounts.