T5 is far from hard.

It's just got a steep learning curve. Everything in T5 is easily controllable and timed with little to no RNG, so as long as you understand the times in-between phases or actions, the fight is relatively straight-forward. Majority of the tactics you need to apply in the Second Coil are those you should've learned during your experience during Turn 5 (staggering DPS, controlling buffs, slightly alternating your rotation). And I am sorry to say this, if you hit a brick wall on Turn 5, you'll hit another wall on Turn 6 once you've cleared it.

Find yourself a competent group with similar goals as yourself and stick together. That's all there is to it.