Although mathematics is the foundation and mechanics really needs tools in mathematical physics methods, the knowledge in mathematical physics methods is not that important. Theoretical mechanics, material mechanics and structural mechanics do not need to learn mathematics, and the knowledge of calculus in advanced mathematics is completely sufficient. The knowledge of mathematical equations is elastic mechanics, plastic mechanics and fluid mechanics, and it is necessary to solve some partial differential equations, such as boundary conditions and initial conditions. However, the development of mechanics has long gone beyond the scope that mathematical equations can solve. Numbers give you the theoretical thinking of people a hundred years ago, but most mechanical partial differential equations can't find analytical solutions at all, and few can really be solved by numbers. This is an idealized theory and unrealistic. The solution of modern mechanical problems is based on finite element method, and the numerical solution obtained is a large matrix equation calculated by computer.
Therefore, learning mechanics well does not need to master the quantity of things to a high degree. Knowing the methods and examples, it is enough to do some after-school problems. Even if you study the number thoroughly, you can't solve a slightly complicated problem of elasticity. You can only answer some questions that simplify the model and conditions to no longer simplify, which is of no practical use.
If you study mechanics, you will study computational mechanics and finite element in the future, which is the theory applied now. In university, basic mechanics will not study too complicated problems, mainly theoretical models and strength theory, and rarely use mathematical equations, let alone complex variable functions. Don't worry too much about counting, it's just a math tool.