A way to implement a custom controller character?

Question

Unity

Hello. The question is extremely short: How to implement a custom character controller? the standard one does not suit at all due to the lack of the ability to change and complicate the collider. Kinematic rb is not suitable as well as manipulations with weight, drag, friction. All due to the fact that such controllers must collide with each other and there may not be a certain number of them on the stage. All that I managed to find in this direction is:
1) Use rb and at the moment of collisions, through OnCollisionEnter, direct the force vector in the opposite direction to balance the momentum upon impact. for late operation of OnCollisionEnter.
or
2) Use kinematic rb and catch collisions with triggers / raycasts / calculation of potential positions in the next. iterations. And it works, but it all just looks when one of them is standing still, and if there are two or more objects, and they are moving at the moment of collision, I don’t know what to do.
How is the standard character controller implemented or how to be?