Fixed that for you. You want muscle, because muscle drives performance. Like Yogi said, you should be fairly lean already. So if you don’t have reasonably defined abs and lowish bodyfat already, you’ve got room to play around with recomping.
What’s your current height, weight, and general fat level? (Not a percentage, just a description along the lines of “chubby”, “skinny fat”, “ripped”, etc. is fine)
Also, for context, what are your best PRs on the big lifts (squat, deadlift, bench, row, overhead press)? Knowing how strong you currently are will give some indication of how to program things.
Size basically comes from training volume and calories. Keep a lid on both of those and you should be fine. Don’t try restricting calories, because that’ll tank your recovery ability and running times, but do monitor your nutrition with weekly weigh-ins (while reviewing the week’s performances) and adjust as needed.
As far as training programs, Dan John’s 40-day approach would be pretty spot-on. Or I don’t see why you couldn’t do 5/3/1 with bare minimum assistance work.
I don’t know what you’re referring to with the “not hitting max efforts too often”, but you pretty much never have to hit a max effort (one-rep max) unless you’re a competitive powerlifter.
This might come as a shock, but not every dude on the site here wants to be a ripped 270 pounds. You’re totally allowed to have your own goals and train for them intelligently. “Approaching your true potential” is case specific for everyone.