Matchmaking is beyond broken

So I started LoL again about 4-5 weeks ago after not playing for around 4+ years. I'm just hear to say Matchmaking seems as bad as ever and is incredibly frustrating to say the least.

I got to platinum within about 13 months of playing when I first started LoL and then stopped. I have been trying to grind up to gold on this new account but it just feels like matchmaking is 100% against you sometimes, I genuinely feel like at most you can make an impact in 10-15% of games you play, the others are decided at matchmaking.

My last 15 games have gone like so:

I won 2-3 in a row, then had a 4v5 which we actually won, then lost then won again and hit promos, I then had a second 4v5 in my last promo game. So just to be clear that's 2 afk from 2-3 mins (not due to ragequitting, just random AFKs/DCs).

I then proceeded to have about 10 games of WLWLLWLWLL or so. Almost all of the losses were completely one sided, and almost all of the wins the same. In the last 5 games alone I have been vs 2 smurfs who completely dominated their lane, one lane on my team which gave over 20 kills in 18 minutes to the other team etc.

The end point is matchmaking is not close, the teams are no where near balanced and you maybe get a good game at most about 20% of the time.