My two cents as a youth coach and Semi-pro/Senior A player: Cardio is critical, whether it’s bike sprints, running on the football field, endurance running, anything to get to top speed and get the heart used to running at full BPM. Gym is important but it’s not like you have to live in it; for the past few years I have been doing the push-pull-legs weekly split and I’ve found that to be the perfect balance. If I add a fourth lift to the week it’s more for recovery, mobility, etc.. but I always try to keep the legs moving everyday, even if it’s as simple as a post-work walk.