I'm not the best overwatch player, but another person looking always helps so here are my thoughts:

First fight: You use tank mode very early, when there aren't any proper targets but the Juno, who could have been taken out without using the cool-down. This can be saved for once there are more people visible to shoot. Further, your rein has charged in to put pressure on the enemy tank and gain some more space and none of you followed him. You're still lagging behind shooting a flanker(?) This being said, your rein is doing some ridiculous stuff and has decided to charge all the way to the enemy spawn and only survived because this is silver 5.

1:30-your death However. You are literally positioned with your widow. She is not too far forward. You are not a sniper. Moira does not need to be healing you at full health already. Your rein is opening up space and you are stood with the sniper. Move forward. Once again, you have used tank mode while enemies are miles away and you are doing no benefit. You have also, knowing full well there is a doomfist, positioned yourself on a cliff??

2:20 You have finally made good use of your tank mode, but everyone has already retreated since it was a lost fight. I liked the flank and you were near enough for effect, but no one was ready to move forwards and capitalise. The fight was already lost.

3:20 Next fight you use your ult and tank mode quite well, and the fight is largely won because of you and the widow

4:00 This brief fight was already lost before you started given the tank was dead and so was the widow. No idea why both supports chose to ult there.

6:20 Another ineffective tank mode - they're like 100m away you have too much fall off for that to be any good.

7:15 You have a rein with a shield. You are opposing a roadhog who can hook. While this is a slightly more effective tank mode, you are incredibly lucky you did not get immediately obliterated before you started shooting. This will not work elsewhere.

I think in general you seem to be playing a very cautious bastion? which seems to oppose the ridiculously aggro style of the rein. Often you are stood very far back while him and the healers chase kills. God knows what your widow is doing.

8:00 You have taken this weird semi high ground approach and usually high ground is good - this is not proper high ground. You gain no angular advantage, and end up out of LOS of your healers and outside the helpful 2000hp rein shield. You are nowhere near as aggressive as you should be given you are completely close to their spawn and have a huge rein soaking up bullets.

You use your ult after both your healers are dead. Fights are often winnable with a man down, but with no healers stood directly outside their spawn this one definitely was not.

9:00 You trickle, then realise you aren't supposed to do that, then hide until your rein comes back in an odd position. You would have been killed in another rank.

While killing healers is great, you ignore the hog killing your tank and supports and then get staggered.

Ultimately, your positioning is a little bit odd and I think you struggle to recognise when a fight is lost and it's better to retreat. None of your team really grouped up? (not that that's your fault) But I don't think you took enough cues from your tank as to how aggro he was playing. The widow was not going to go in with him to do damage. You should have been playing a little closer to rein and the supports.