This is imo the best build for zephyr, although tbh its not that interesting to use.
Build -
I run with the [Stropha] build here using a combo based heavy atk build and [Ignis Wraith] build here, but primary is more or less prefernce although beam based primaries work best with tornados. I also use primary and secondary dex arcane with naramon focus school so I can build combo with stropha and more or less forget about it till I need it.
Gameplay -
Just chuck the 2nd, 3rd, and 4th ability in a spot and sit in it spamming with the [Stropha] normal atk or hover using the 1st ability and holding left click on a tornado. Both methods will provide you with near infinite energy and kill all regular enemies, if there is an enemy that is taking a while to kill then simply build some stropha combo and heavy atk.
Acolyte -
When an acolyte comes build your combo with [Stropha] and proc both arcanes before heavy attacking the acolyte. This is almost a guaranteed one shot if its affected by your tornados, and if its not then it'll probably still one shot anyway.
I haven't been bothered to test just how far this will get you in a steel path endurance but it easily clears about the first 2 hours. The brunt of the dmg is coming from the [Stropha] in form of strait up dmg as opposed to armour strip or slash procs so I don't imagine that it could take you to the level cap but if you want to try the sheer power of [Stropha] + tornado may prove me wrong.
Thank you.