Yeah listen to PX, his back > Rockell’s back 
On a more serious note, I think dropping exercises name is almost useless as, like we see in this thread and with the pros, there are many ways to build a big/thick upper back each as effective as the other, depending on the individual
OP have you been using wrist straps? I would give them a try if you havent. Also giving back it’s own day(s) could help. Agree with using a little looser form on heavy compound movements.
My back has got fairly big from Deadlifts , heavy snatch and clean pulls for sets of 3 and heavy cheat DB rows.
I have noticed recently my back has gotten bigger from doing overhead squats and overhead supports in a powerrack. Especially the overhead supports holds of various times 5 secs , 10 secs and simply locking out.
I think working up to double bodyweight would build some big backs.
The upperback cramps up like nothing else. I think it has to do with working it isometrically over a longer period,
I get the same feeling with 3 quarter range presses in the powerrack.
Also steel bending is great too , once you already have a strongish back.
Variation defintely has its place. Plus I would substitute the deadlifts for rack pulls and shrugs for bodybuilding.
Strict straight arm pulldowns (or towards you really hit back nicely too). Tried the same thing kneeling too works even better.
Specialization is for insects.