Calculation of MOSFET gate drive current
the method you are persuing is calculating the average current needed to switch a MOSFET. This is one part of the calculation as one of the key need is the peak current to ensure you are switching fast enough.

what the best way to calculate Rg gate driver for Mosfet

As far as your calculations are concerned, this is only half of the calculation.

Every switching period has two switching edges


Turn on
Turn off


Each edge requires the transfer of charge (in your case 94nC). If you half the period you will be closer to the average current flowing.

The other approach is to calculate the rms current

\$I_{rms} = \frac{1}{R_g} \sqrt{ \frac{\int_{0}^{period}(V\cdot e^{-t/R_g \cdot C_g})^2{} }{period}} \$