If it were me, I'd try to isolate the faulty component as a first step. I can't quite make out what you are saying in the video so ignore this if you've covered these steps already.
First, remove your rear wheel and the brake pads to avoid contamination with mineral oil; next, disconnect the brake hose from the caliper. Then try to move some mineral oil through the caliper with your bleed kit. If you can't, you know the brake is faulty.
If the path internal to the caliper is clear, either the hose is blocked (unlikely) or the hydraulic module within your shifter is borked.
