How do people get absolab on new boss Mules?

Or even get to the point of being able to kill Lotus and Damien.

This might be a silly question to some but truthfully without hyperburn I have never been able to do those bosses in any of my boss mules, and I’m starting to ask myself how people usually do it??? Is this where a struggle party comes into the picture, how does the struggle parties even work? Everyone get coins and crystals?

I have almost 8k legion, and 6 akechi boss mules, would love to get them to the next level.