So just a few things. You contradict yourself a bit. You say you are making space? But then you say the enemy Rein is deep in your team suffocating them and wreaking havoc. That is a contradiction. You have not given your team any space if you allow their Rein to rum amuck in your team. You have all the space in the world, your team does not.
Now saying that ,you could be doing your job well, technically, so long as you are getting a kill every time you dive backline. And you should dive the backline, get a quick kill, then back out and reassess the situation, check on your team. Rein is in your teams face? Go deal with him and make some real space for your team.
But if you’re chilling in the enemy backline and the enemy tank is 1 or 2 v 4’ing your team and winning, then their tank and its pocket/helper is better than your 4 teammates. This ‘shouldn’t’ happen on paper as they’re outnumbered, but it does happen. The enemy rein is capitalizing on the fact that your team doesn’t have a tank presence to directly help them, and if he hits all his abilities and wipes out your team… That is both your teams fault and your fault.
This is a common thing for DPS players to blame their team. They can go in the enemy backline and get 3 picks, and lose the fight. They scream “Why TF did we lose the fight? You guys suck! I got 3!” meanwhile the enemy DPS (or tank) also did the same thing and killed 4 or 5. Awareness is key.
Remember you are the common denominator in all of your games. You can never truly put full responsibility for winning on your teammates because you don’t know if they’ll hit their shots or be in a good position or not. You have to take full responsibility yourself, ask yourself what you could have done differently. Did you linger a few seconds too long in the backline? Did you take too long to net a kill? Are you dying outright while taking aggro? Are you neglecting your teammates? Their survival should depend on you, either killing the enemy faster, or peeling for them to kill the enemy on top of your team.
A great YT/streamer to watch is Awkard. He’s no nonsense, you watch him, follow his tips, you’ll improve. I don’t think he’s done a Ball UtGM yet though, but his tips can apply across the board. The general gist is, never rely 100% on your team to win. You need to kill and you need to stay alive. Don’t trade, ever. Even if you can kill 2 with you dying, it’s most often best if you live because your dying then makes you rely on your team to win the fight, putting full responsibility on your team and not yourself.
And in order to keep killing and to stay alive, you need your teammates alive. You can’t expect to win if your teammates are always dying. You need to keep an eye on your teammates. He’s called a wrecking ball for a reason. You can dive enemy backline and return to protect your own backline within seconds. Swing from backline to backline like a wrecking ball.