It's amazing to see you got 9 kills with just around 900 damage. After seeing that gameplay, I have some tips for you. You can use if you want.
While using a shotgun, try to cover and shoot.
While you were using the Phoenix Kit, you can clearly see where the enemy was shooting from, but you turned right
Also, while reloading/healing, don't rotate around in a tight space/corner as one side is just a wall from where no enemies can shoot at you
2nd clip, not sure why you're holding R301 and waiting for bloodhound push when you got a mastiff in hand
You deployed health drone in a bad spot where you were exposed