I was checking if I could play on the ping difference with you but realised it was too high once I joined so I spectated a bit.
I got dropped to silver after my unlucky run with Churba at the end of last season. (I didn't realise a bunch of new people would just play placement matches at the end of the season so ended up dropping 500 points in 10 games.)
After doing my placement matches, the people have been ok to middling however I see those toxic personalities more in quick play then competitive. As you've seen,all you have to do is mute and report them.
I would recommend at your level you need to hard carry the team, because you can't expect the team to know how to aim or know how to block (like Dva players at this level will just sit there shooting and forget that she has the ability to block all incoming damage, Zarya's don't know how to build up charge, Reinhardts are too aggressive with no backup).
People generally just waste their ults when the fight is already lost.
I'd recommend picking up a few self healers, like I don't have many hours on Soldier or Roadhog but can do far better in terms of winning the game with them than Tracer or Zarya. I can also sometimes carry a team with an Ana by calling out what to do but if no one is in the voice chat it's hopeless. Also I noted you were playing Sombra which requires insane amounts of communication to pull off or just really stupid enemies.
A frustrating thing I found today were groups of assholes who wouldn't join team chat and pick champions that they ended up being very poor at. On top of that you couldn't communicate any strategy or even basics like changing off a key character like Reinhardt to Junkrat and expecting people to notice or shuffle the team composition accordingly.