I’d still try to get out of the reliance on heal as fast you can. This game is designed in a way that the boss will eventually outdamage your healing cooldown or the time limit is going to mess you up. Focus too much on healing and surviving, you’re not going to do enough damage.
And before people pointing out that there has been example of people soloing the catastrophe rags, I’ll also point out that it took them 50+ minutes to do so and theres only 60 minutes time limit. Also, its probably not something everyone can do.