Pharah alone can’t decimate my team, unless she is exceptionally good at flanking from above (eg, don’t reveal her position until the ground fight starts), or my team already is in shambles and running in seven different directions like stray wild cats.
In both cases, no matter how good you are at a hitscan long range hero, you will still be in trouble. Because that’s great teamwork supporting Pharah, or terrible teamwork leaving the enemy team free to do as they please.
Teamwork always wins against no teamwork. No matter how skilled each individual is, if one team is acting together, and the other is not, they win.
In the case of a great team supporting their flanker Pharah, you treat her like you treat a good Tracer. You don’t engage until you are 100% sure where the flankers will come from, and force them to regroup with the main force or die before the fight start. And this don’t require a long range hitscan. If you have Zen, Orisa and Hanzo spamming projectiles towards Pharah, she will run away. Then you attack.
The problem is convincing my team to NOT PUSH until we have dealt with the flanker. You know how trickling works.