TLDR: My handbrake has been almost non-existant for the past couple years (car moves easily on an incline as if there was only a tiny amount of resistance). I replaced both rear calipers but it hasn't helped with hills at all, still the same. When jacked in the air, both rear wheels are solidly held when the ebrake is engaged so thats an improvement over before but on hills its still the same exact issue.

Did I mess up the installation process with regards to the cable? Was I supposed to set the handbrake cable in a certain order before installing the calipers? Could the cable be an issue and should I replace it?

Long Story: My handbrake pretty much hasn't worked, as in the resistance it provides is too weak to keep the car from moving (tigthening the center console bolt doesnt help), ever since the car had its pads replaced by some shoddy mechanics (who put the pads on in the wrong orientation).

I decided to replace both rear calipers because I believed one of them was defective (it didn't push its cylinder out when the ebrake was engaged). Replacing the calipers was pretty simple but afterwards I noticed that there was no ebrake at all. Like not even a little bit. But after googling I realized that engaging the ebrake lever before installing and running brake fluid through the caliper is a big no no. Then I learned that I could reset the calipers by pressing in the caliper all the way. Afterwards, both wheels had ebrake (with the car jacked and the wheels in the air)! Eureka!

But the joy was shortlived because as soon as I tested the ebrake on an incline it was the same old story. Absolutely the same amount of resistance as before. I tightened the center console bolt all the way down and absolutely no gain in resistance. And I had to tighten it a lot, like many rotations. What could that mean? I figured that the more you tighthen the bolt the less slack there is in the ebrake line. But I tigthened the bolt all the way, and a long way, so how could there be that much slack? There was enough tension in its original position to grip the wheels when the car was in the air, how could turning the bolt about 20 times not increase the tension?

When I installed the calipers the ebrake bolt in the center console was really really loose. I had unscrewed it a lot just to be safe and also because I wanted to pull the ebrake cables out to secure them to the calipers. Was I supposed to the tigthen the bolt more before "setting" the ebrake on the calipers? Could there be an issue with the ebrake cables? I figured the cables work because I thought of them as being a binary, they works or dont work. Could there be another issue?