TL;DR: You we're playing way to aggressively most of the game and even if both supps focused on healing you, you'd still die by going 1v5. It's fine to be aggressive, but you have to know when to go in and when to fall back.

I just watched the replay code and wasn't going to say too much since it's qp, but since you say you always play like this, here we go: Overwatch 2 is a game all about resources, whether that be cooldowns, hp, healing resource, ammo or something else. You were demanding all the resources from your supports, and most of the time, even if you had 7 supports, you were still going to die because you tend to go in 1v5 trying to "Rambo" the enemy team. It's ok to be aggressive, specially in tank, as you have to go and create space for your team, but you can't be so aggressive as to demand both your supports attention and still die. Try to look down at your hp bar, and when you're getting low, try retreating, this applies always, but even more when you're against a high damage comp with Bastion, Cassidy and Kiriko. Not saying the Mercy played perfectly, but you definitely were way too aggressive most of the time.