I am still struggling to get pull-ups, I have done negatives previously, any suggestions?

The biggest thing that helped me doing pull-ups and getting my numbers up was to build up my grip strength by hanging on the bar longer than just for my pull-ups. For example, just hang on there for an extra 30 sec and do reverse shrugs where you flex your back to make your scapula retract if that makes sense. Additionally, I am not sure exactly how strict you are being with your protein intake but that is also a big factor that people end up neglecting.