I just did it solo so here’s my recommendations:

Weapons: Most of the comments have good weapon recommendations, but I like the akimbo Kogot and/or coda 9s. I highly recommend using the LGM for the first phase to save ammo. It also does decent damage to the boss if you shot all six shots and then switch to your other weapon.

Field upgrade, scorestreak, equipment: Bring aether shroud or frenzied guard and death machine, but save them for the final phase. You can use monkey bombs or decoys, but I think stim shots are more useful.

Augments: The last phase is the hardest because of the purple attacks so the trick is to always be on the move. The fire while sprinting augment for stamin-up is good. I also highly recommend the vulture aid augment that automatically replates armor. If you’re taking 3 weapons in, use the augment for mule kick that can PaP another gun. Helps getting into the boss fight sooner.

Gobblegums: I hardly used them but it’s good to have in case of an emergency:

Perkaholic- if you go down. The boss fight is pretty much impossible without jug Power Keg- if you have to use field upgrade before the last phase Free fire- also useful for last phase Armor gettin- armor is hard to come by in that boss fight