They seem about equal. At the same dose (15 g with vitamin C), both raise the same amino acids in the blood. The marker of collagen production rises about 20% with either one, but the gap with placebo is not significant (small study of 10 men, Lis and Baar, 2019). Hydrolyzed collagen dissolves in a cold drink; gelatin does not. Both come from animals.

Maybe a little, on top of exercise. In a pilot study of 20 patients, 5 g a day of collagen peptides added to a calf-strengthening program improved the pain and function score faster than placebo over 3 months (+12.6 points vs +5.3; Praet, 2019). The study was funded by the manufacturer and needs confirming. Exercise remains the core of treatment.