Unlocking epic destinies

[Plex1975]

I am a bit confused of how the unlocking of epic destinies work after completing my first eTR as divine crusader.

I want to unlock the martial sphere and later the primal sphere, do I need to max xp in Unyielding Sentinel to unlock Grandmaster of Flowers, then max xp in Grandmaster of Flowers to unlock Legendary Dreadnought+Shadowdancer and so forth?

Or is there a shorter way to unlock Legendary Dreadnought and later other EDs in the primal sphere, which include skipping of less interesting EDs like Unyielding Sentinel and Grandmaster of Flowers for my build?

My heroic character is a paladin and I dont plan to change class from tank-like builds or go for completionist