Repelling Bastille augment lets u stack your Vortex duration
For example this build make Bastille/Vortex last 14,25 sec and u cast another into 1st one
And it will add to it 70% of its max duration which is 9,975 sec (almost 10)
So each additional Vortex u cast into existing one will add almost 10 sec to its duration
So 14 > 24>34>44 and so go on

You can stack up single Vortex at max to 142 secs

I use this build only for Vortex im doing liches with this build missions are easy especially excavations defenses and any kind of mission u need to [Protect] something
But fairly good for exterminations also

If ur on defense try to trow [Flechette] (press 2 until RED ICON is selected and then hold 2)

Its kinda doing all the work for u in conjunction with vortex

I would consider rank 4 Fleeting Expertise and Stream line to gain additional duration on vortex

I suggest to supplement ur ass with

Venka Prime
https://overframe.gg/build/8179/

Or

Gram Prime
https://overframe.gg/build/8541/

or

Reaper Prime
https://overframe.gg/build/8716/

or

Ninkondi Prime
https://overframe.gg/build/2364/

iIsane attack speed + [Healing Return] + CO heals u in second from 1 hp to ur max hp