Should I

[Zylx]

Okay, tbh I kinda wanna get mythic helm and armor and just upgrade armor and get Grimm for rogue, is helm really good?

Might as well craft both tbh if you are crafting one or just use a alternative from mythics just in case they release new gear from Halloween or planar

There is also the "Acquired Restored Mythic Armor" acheivement. Mine didn't get completed until i upgraded the helm though.