A very simple arcanist build. Be flexible to what you need to bring to the group. This guide has been written with several other experienced players to bring a tried and tested setup for Update 50.
My attached parse is a very straightforward one capable of approximately 140k.
If using
Exhausting Fatecarver over
Pragmatic Fatecarver you may wish to swap out your off hand daggers enchantment to absorb stamina. I would recocommend parsing in exhausting fatecarver if you can sustain it, but using pragmatic in content for the very valuable shield.
Variants of this set up include with Null Arca + Deadly Strikes, and Null Arca + Morag Tong to offer support to Necros / Nightblade's in the group.
You can also run this with the shattered paths mythic, just swap velothi to the matching jewellery piece.
You may also want to change Cavalier's Charge to Class Flourish.
I have also attached my old subclass set up which I still use in dungeons from time to time.
This build (and its subclassing predecessor) has cleared HM trials, dungeon trifectas and more.
Rotation:
For parsing, pre-buff by casting cloak, scholarship and rune. Try to be on 3x crux before the fight if possible.
Open with stampede into the eye ultimate, then flail once to apply Abyssal Ink, then if on 3x Crux, beam immediately. Once this ends, flail once (you can spam the button so this goes off as soon as beam ends), then bar swap to cast Fulminating rune, then bar swap back to resume flail until 3 crux then beam. You do still want to light attack weave where possible to generate ultimate.