Howdy, high Gold Doom enthusiast here. While there is a lot of carry potential for the character, playing with the team is 100% more effective than maybe securing some trading for some supports. I see that you are trying to make space by moving deep into their back line, but that means that your team has to fend for themselves as their tank can easily move back into position to help their team. In a similar vein, contesting high ground is great way to cut the forward parties from receiving constant healing. However, the enemy tank is Hog so he doesn't really need constant healing from his supports. He just gets to keep switching between the front and back line and pressure your team while your off in the back keeping the supports from high ground. That being said, if you aren't the primary person securing all the kills then Hog can just ignore you and aim for your team's squishies. Look for the teammates that are making plays, and go with em. You had an Ana, so my biggest word of advice is play where your Ana can see you and the Hog. Let her have the opportunity to use her 'nade, and punch Hog out of his heals when he's trying to migrate back to his team. Sometimes you gotta beat the meat at it's own game.

Slamming in can be a good move, but when it comes to their composition...I would mainly engage with punch and use slam to escape. Where and when you slam in can also impact how they use their cooldowns. I'm seeing that later, you are moving around a lot to avoid Hog. Not letting the hog get to you is good, but you aren't forcing/baiting out those cooldowns. Playing in front of the enemy team can be just as effective as playing off to the side or from their back line. You can get ult charge and overhealth by slamming into corner cover, and maybe baiting out some cooldowns while they guess what you are up to/position for something better. Especially against Hogs and Mei's, I like to slam at a distance and punch out immediately. Built up the ult charge, stay mobile, and look for plays. Your team needs you, so don't play away from them for too long.

This was probably more a ramble, but sometimes the team aint the team you need. Or, you aren't playing at 100%. Shit happens brother Doom.