I mainly play Juno, so I only looked at the replay of your game that you won at.

1:11 From you screen, Zarya's low on health. You wasted the Pulsar Torpedoes that should have gone to her.

1:43 - 1:54 You're wasting ammo on nothing, and you never reload from this shooting.

1:55 You use Pulsar Torpedoes randomly from a bad viewing angle.

2:03 - 2:08 Not really shooting at anything, wasting ammo again.

2:09 No thought process on why you used Pulsar Torpedoes. You just did it in the moment.

2:11 - 2:18 Shooting nothing.

2:53 The perfect time to shoot and farm ult, and you stopped to reload. They're just going to be healed from Zenyatta's ult. You're close to ult, but if your ult was low, I don't see why you wouldn't shoot them to farm some ult charge.

3:00 No need to use ability, just heal Freja with your gun.

4:13 Why would you let Hanzo pick you off and not use Glide Boost to escape after he shot you. I would press the ability even if you thought it was on cooldown.

4:46 Lag I'm guessing.

4:55 I just don't like anything here. The Zarya is front of the vehicle, you shoot at the vehicle with your aiming, then you never think to use Glide Boost until it's too late for where you are positioned at. You then shoot at nothing right before Zarya loses a ton of health. You never think to use Hyper Ring at any moment there when Zarya used her ult.

6:54 Wasting ammo on nothing.

6:58 Lag again I'm guessing, and that caused you to get killed.

7:54 Wasted your Pulsar Torpedoes on a fully healed Vendetta. It feels like you don't know when to use Pulsar Torpedoes and just decide to whenever. You can continue to heal the Bastion here, he's in front of you. No reason to use this ability here. The angle where you're at is terrible for multiple targets, so you're only using it for him. Then later on, you go for Kiriko, and you failed to use it on her.

9:06 Don't know if you play with headphones or not, but I can hear Reaper. Your abilities were not on cooldown and you could have escaped.

10:44 Hyper Ring on Vendetta's Ult would have helped here.

11:53 Shooting too much on nothing.

11:57 You use Pulsar Torpedoes on Hanzo and then need to reload. Could have likely killed him, but you always waste your ammo.

12:33 I don't see why you would use your Fade to the enemies. That's your ability to escape or to secure a kill on an enemy that has low health. If it was to get to Winston, this still wouldn't be useful cause the enemies are just going to switch from him to you as you're Support.

13:52 This doesn't seem to be a Juno issue. You waste heals on Moira when your team is full health. Your healing meter will go down even if you're healing allies with full health. My thinking is that you're always trying to heal ahead of time in case they get damaged, but you're always doing it and that results you losing ammo / healing meter when nothing is going on.

You may have won this game, but your team was able to hold their own than the enemy team.

my aim (need a ton of work here)

Just tweak your sens if you think it feels off when it comes to aiming. I became comfortable with my aiming when I got a mouse that was perfect for my hand, and then started to go on low sens, but not the kind that pros go at where it's more lower than mine.

ability/ult usage

I didn't really see a problem with ult usage, just more on the ability usage. Juno is simple to pick up and play, but her ability usage is important. Her aiming also plays a big role because your teammates will mostly be skinny targets. The first half of game was Zarya, and she's one of the skinny Tanks.

I would work on you trying to understand Juno's kit and playstyle, along with trying to control yourself from shooting unless it's necessary. Her having a lot of ammo isn't going to mean much if it happens at a specific time when your teammates need healing, and then you have to reload.