I’ve read that jelq exercises can affect length negatively AND positively. Maybe what you mean specifically is that jelqing affects length gains in making them more difficult to procure. This does appear to be true based on the reports here, and even I have experienced it to a slight degree. My girth went up a quarter inch, and my length gains slowed down. But that also could have been due to reaching a plateau.
As far as what to do, far be it from me to tell you since I’m not one of the more knowledgeable ones here. However, my recommendation would be NOT to cut the jelqing altogether. Your gains may not have cemented. Try stretching, with reduced jelqing to keep your penis fit and limber in all directions. S’my 2 bits, whatever it’s worth
11/2/05 5'8; 180 lbs, 35 waist BPEL-7.2, NBPEL- 6.0 EG- 5.0-midshaft There is the man I am, and the man I can be. Someday, they'll meet.