Traders are perhaps the best profession for soloing S7. Here are a couple videos demonstrating their capabilities (self-buffed).
See the video descriptions for the setup used. The mini-bosses are pretty easy, but the Technician can be kind of hard. I’ll put some notes about that fight here:
The Technician fight shows off a lot of the Trader’s strength. It’s possible to take the Charging Tower down without the 30% Reflect drain (I’ve done it), but it’s really risky and you’ll probably die. You want to grab 30% Reflect before the fight (I grabbed it from Milo Chatter). If the Charging Tower comes before a Drone spawn, you’ll most likely still have the initial 30% Reflect running. But during Drone spawns the Technician raises a Reflect shield, so you get a chance to redrain. Drone spawns are something to look forward to when playing a (self-buffed) Trader.
And Nanobot Defense is the perfect tool for dealing with the Drones. They explode 30 seconds after their spawn, so keep your nano topped off and cast Nanobot Defense right before they start exploding. You should have time to kill 2 of the Drones before the rest start exploding. You can swap a Physics Reflect Bracer on for extra survivability during this phase (their explosions do Radiation damage).
The Technician only does Melee damage, so a Melee Reflect Bracer is recommended, especially during the Charging Tower phase.
And watch out for timing problems. I had to stall a bit during the above fight because I used some cooldowns and wanted to make sure they were available when fighting the Charging Tower.