its all about the Yellocake Launcher in combination with an Atom Balm Victory Rush (looking for a better one but its about the passives) Launcher: M10 Yellow Cake, with 200%dmg While Action Skill
Shield: Echidna Old God: +20% rad dmg
Artefact: Atom Balm Victory Rush: 20% Radiation-dmg, 40% splashradius
Classmod: RedFang: 32% indirectly dmg, 26% COV dmg, 22% Radiation resistanz
these are the main things to use.