Make it so that everyone gets the same Legendary Augments to choose from when the choosing phase is in.
The RNG factor will still be present because the regular augments will be randomized.
this will also solve the issue with some people complaining that someone won cause they got wave, meteor, or lights chosen, etc
since we all have the option to choose from the same Legendary Augment.
I believe this will make things much more interesting and balanced, still with an RNG factor.
Just like in arena where players get to choose from same legendary augments, but put it in Gauntlet
(without the gold points choosing of course)
In addition to this if you want to make it even more balanced, you can nerf the Meteor, Lights Chosen, and Warpwave a bit for example:
Meteor -> lower stun time or the amount of players stunned lower by 1
Lights Chosen -> lower to Holder + 1 ally instead of Holder + 2 Ally
Wave -> lower stun time or energy gain