"The maxes" can be substituted with a variety of synonyms depending on the context of the sentence. "Maximums," "peaks," and "pinnacles" all refer to the highest point or limit of something. "Ultimate" and "supreme" also convey a sense of being the highest or most important. "Summit" and "zenith" convey a similar idea of reaching the top of something or achieving the ultimate goal. Additionally, "full throttle" or "all-out" could be substituted for "the maxes" when referring to giving maximum effort or energy. Overall, there are many synonyms that can be used to convey the idea of pushing to the limit or achieving the highest point of something.