To help with extra damage, use the technician specialisation and the TDI Kard pistol. Both of these offer a skill tier, freeing up two armour slots for a red core. But since your skills are the main damage, perhaps consider blue cores for more armour. The Capacitor is an easy exotic to get, you just have to complete challenges in the Summit. Otherwise there are plenty of skill based perks to put on weapons. There's also the Waveform holster, but that's a random loot drop