The Yang-Mills field is based on the symmetry of the strong force; however, experimental asymmetry problems arise, leading to the theory not being entirely correct.
In his book "The Universe Is a Unified Object," author Ngo Quang Ha demonstrated the structure of the electromagnetic field, the electroweak field, and the strong force.
Therefore, the Lagrangian equations of the Yang-Mills field all need to be revised.
At the same time, the author demonstrated that the strong force field asymmetry creates mass for the gluon.
The book (in English) is available on Amazon: https://www.amazon.com/dp/B0HCGYPFK1