Support playbook

Setup & first fight

Stand a little behind or beside your tank, with sight of your team, cover one step away and an escape route picked before the fight.
Staying alive comes first. A support who dies early forces the rest of the team into desperate plays.

Heal by need: the diving ally about to die comes before the tank who can wait.
Keep big defensive cooldowns for real threats. Spending one on chip damage hands the enemy a window to go in.
When nobody needs healing, shoot. Support damage forces cooldowns and finishes low targets.
Keep track of enemy flankers and ask for help early and specifically when you're dove.

Use a defensive ult as the answer to the enemy's big commit: not before it lands, and not after your team is already dead.
Track a few enemy ultimates rather than all five: the one that wins fights and the one that saves them. Judge their charge from last fight's damage and healing and from how long ago they used it.
Avoid stacking two ultimates to win one fight, especially into a counter you haven't baited. It leaves you behind for the next fight.
After a lost fight, stop taking extra peeks. Back off, meet at one spot and go back in together, because trickling in one at a time loses the next fight too.

Overtime only holds while someone alive is actually on the objective (point, payload or robot). Standing near it doesn't count.
In a round's final fight there is nothing left to save ultimates for, so use them freely.