Once dynamic equilibrium is established, will it shift if additional reactants are added?
Yes, in the forward direction.
le Chatelier's principle tells us that the position of equilibrium will change when we change the conditions, in order to minimise the effects of the change.
If we add more reactants, the position of equilibrium moves in the direction where reactants are used up (creating products) i.e. the forward direction, to minimise the effect of the extra reactants.
This is what is done in the Haber process to keep producing ammonia. The unreacted nitrogen and hydrogen is mixed with more raw material and recycled back into the reactor, forcing the equilibrium to adjust in the direction which creates more ammonia.