The rank is the measurement of time dedicated to the art, and your movement is a reflection of your understanding.
When most people start martial arts they may have a goal of getting a black belt. But hopefully over time they understand the essence of training is understanding the movement, development of oneself and helping others. Rank is a byproduct of training not the reason we should train.
Throughout our journey through the martial arts our goals or motivation can change. If competition enters our goal set, that title or gold medal can be a long way off. Our motivation is an extrinsic goal or motivation. but in reality we need something more internal to maintained our motivation and engagement. Strategies and working new game plans can allow creativity and keeps the motivation in each class. It allows the students to engage with short term tasks and works on mastery of skill. This will allow students to develop new physical skills but also maintains interest.
In martial arts we understand that repetition or drilling down on a technique can be imperative, it allows the mastery of skill to develop, but keeping students engaged through that process untill they can grasp the concept can be challenging.
Good luck in your training!