Playing two sports & trying to get stronger? Dont bother man. If you can go through two sports, and KEEP your strength, I’d consider that a Win.
As far as the “increase deadlift by not deadlifting”, I wholeheartedly agree. I agree because I’ve got a chronic back injury that comes up when I pull week after week. So I took about 3mo off and hit an all-time PR. Would I have done it without the time off, I really doubt it.
You can get stronger on deadlift with squats and vica versa. IMHO.
Another thing, I strongly believe to get stronger pulling heavy you need to pull heavy. I got my greatest gains from pulling against doubled mini bands. It taught me to pull hard and fast. I know there’s the get stronger by doing different but same idea.
But for me real world was getting stronger by doing the lift and constantly improving form. there is so much to staying tight on the bench and holding tightness when you squat, not rounding your back on a deadlift etc.
Assistance exercises can help correct weaknesses, but get stronger also seems to work. Example. My son did a rough 355 rounding his back in June or July. He just missed 405 a few weeks ago. His form got better as he got stronger. So is it the chicken or the egg?