u/UnhandledExceptions

I was finally able to beat the Operator Mastery. I tried so many different styles... drone, kinetic, precise, elemental. Easily beat it when I basically ignored the starting drone on upgrades and got the krakatoa sentinels, cryo cannon, and corrosive sludge pump weapons by using the artifact that allows access to beams. Pumped up those three and I could basically just sit through swarms; flame throwers burning them down and extra beam cryo causing them to stop.

I hope this helps someone else that is struggling with this one.