Whether it’s work or a workout regime, giving your max effort to something doesn’t mean going full throttle at that thing all the time.
Your max effort at something is determined by your consistent best effort at lots of different things that impact your performance.
Giving your max effort to something requires understanding all the different things that help you perform at your best and investing adequately in each of those: rest, recovery, relationships, mindfulness, nutrition, and play, are just a few examples.