That was all okay because of his energy being as vast as it was and with it's recovery speed it was also not an issue. John was going through this same drainage for not just magic but for everything else he was basically burning a world's worth of unnecessary energy whenever he is going all out like he was with his past self when he was being killed. He was also not controlling his might well enough. He was wasting strength or going faster than necessary, not going fast enough or being strong enough his endurance durability everything was unrefined wasted ability. John began to train himself to get rid of these flaws to bring out his maxim best self he was also training his healing abilities illusions he was doing nothing but training. 50 years later John returns to the public after obtaining perfect control he was now an unbelievably more powerful individual however he was also elderly and that made his body weak. John became a monster hunter for twenty years then he became a mercenary for another 20 years before becoming an assassin for 20 more years he then became a Holy knight for 20 more years before becoming a knight for 20 more years. John was keeping himself alive through his own might energy and power magic spiritual abilities keeping his body functioning this was granting him the ability to keep up and keep going he was gradually growing stronger through this as well simultaneously taking on these job occupations made him stronger through combat and experience but also as his resistances and stuff were being spread out to keep himself alive he was gaining greater resistances and defenses he was improving in all areas. Then he became an adventurer for 20 years.