Get rid of the whole thing

1. Screw the permits.2. There are many outdoor gyms on compacted ground. Just keep brick, level and add rubber mats. 3. Add 2x4 to make it 16 oc.4. Get insulation and drywall in Home Depot and put it in yourself. If electrical is good, no need to mess with it. 5. Add small spar heater and cheap fans. 6. Keep door and open for fresh air when working out.
   In conclusion, it’s a workout space to bust some reps and make some gains, so make it useable. Invest some dough once you decide to live in it or rent it out.

I would go in behind it with needle nose pliers and back it out a bit . Then, switch over to locking pliers and twist from the fromt

Btw, if you plan on making more. Cut down on time by using long sheet of steel and cutting the lines just deep enough to bend metal into shape. Then, fold and weld one edge. Good work