How do we work hard inside real limits without resentment?

You are working inside a real limit — money, time, people, or all three. You have not resented it, and you have not used it as an excuse to coast. That already puts you ahead of most teams. The harder pull is different: the urge to push past the limit anyway, to work late or take on more, just so you can say you tried hard enough. That urge is not diligence. It is proving. And proving is a different job than doing. When one person on the team pushes past the edge to look committed, others feel they must match it, and soon the whole group is spending effort on appearances instead of results. The skill you are building together is knowing exactly where your power ends. Inside that line, work fully. Outside it, stop pretending more hours or more strain will help. That is not weakness. That is aim.