Tbh the flex is the part that's hurting you, not helping. A wobble or flex extension changes the actual torque you put on the bolt, so the wrench clicks clean but you're not really hitting 40. For tight spots you want a thin wall straight socket or a short rigid adapter, not something that bends.

The heat trick works even better if you warm the panel from the back side and let it cool slow after you push the dent out. Keeps the metal from getting stressed and those little sharp crowns don't come back. Learned that the hard way on a black truck hood that showed every ripple in the sun.

Did you size it for the press startup draw?