'06 Chevy Silverado Rear Brakes Won't Bleed

Hello guys,
Long story on my ’06 chevy silverado 1500 brake job.
1) I had an ABS light and my scanner said it was the RF wheel speed sensor.
2) I changed out the sensor, did not fix the code.
3) I replaced the wheel bearing, did not fix the code.
4) I then made a bright decision (slight sarcasm) to rip off the ABS module, resolder some of the main points, and plug it back in. Did a fancy job, besides breaking off one of the brake line holes in the module. I plugged it in for fun, and it surprisingly enough did fix the ABS light.
5) However, I went to a junkyard, got a new module (kept the old circuit card up top cause I knew it was good now* supposedly*)
6) New module in place, decided to start bleeding the brakes. Crazy hissing sound coming from the crossover line. It was broken. Another long story short, I replaced that brake line.
7) Now I’m going crazy, but it’s time to bleed the brakes again. I started with the back, but it had nothing. I then went to the front, and everything went smooth. Went to the back turned on the truck, cycled the brake pedal multiple times, nothing. I decided to purchase a handheld vacuum pump for bleeding brake lines off Amazon. It did well getting a bit of old oil out of the lines, but nothing budged. I then watched a Youtube video stating that I need to slam on the brakes to activate my ABS pump to burp the air out of the module since I replaced it. I idiotically went around my neighborhood slamming on the brakes. I turned back and there was no pressure on the rear line. Finally, I decided to rip my car battery off, took the leads off an old fluke I burnt up, and manually actuated the ABS pump. The pump ran great, but nothing came out of the back line even with the damn bleeder valve completely off. (I initially ran with it tightened so it would build pressure and then I could release it)

At this point, I really don’t know what to do to get these damn brakes bleeded. Any ideas?