Is it obligatory to make up prayers and fasting for the years during which masturbation was practiced without knowledge of the religious ruling and without performing ghusl, despite attempts to remember but without success?

Praise be to Allah for your recovery. Please refer to Fatwa no. 135789. If you are unable to ascertain with certainty what you need to make up, then act based on your best judgment and make up what you predominantly believe will absolve you, for Allah does not burden a soul beyond its capacity. Please see Fatwa no. 142278. Your doubt about having intercourse during Ramadan does not necessitate making up the fast, as the default is innocence and the validity of the fast. However, if you are certain of having had intercourse while being ignorant that it breaks the fast, then there is a difference of opinion on this matter, which we have explained in Fatwas 109440 and 102809. And Allah knows best.