why current is called the fundamental unit while it has the relationship with v and r and also tell me the dimensional formula of current?

Current is not defined in terms of force, it is simply the number of electrons that passes a certain point every second.

Voltage is analagous to force.

 

SI units are defined the way they are because the definitions can be implemented precisely in the real world, not because they are ideally logical. With our technology it's probably easier to measure forces between currents precisely than it is to measure forces between charges precisely, or to count electrons directly.