you can start with the ground speed and wheel diameter to get the wheel rpm,
next use the wheel rpm times the gear reduction (wheel teeth / motor teeth = gear reduction) to get the motor rpm.
next use motor rpm / motor kv to get the back emf v,
then use ((pack v * duty %) - bemf v) / winding resistance = motor current
then 60 / (2 * pi * kv) for motor torque in newton meters per motor amp
then motor current times the torque per motor amp for motor torque
multiply the motor torque times the gear reduction for wheel torque
vehicle thrust comes from relationship between the wheel torque and wheel diameter-- (wheel torque in newton meters * 1000mm) / ((1/2) * wheel diameter in mm) = vehicle thrust in newtons per motor
then you can get the mechanical watts from motor torque in newton meters times motor angular velocity in rad/sec
electical wattage is (pack v * duty %) * motor current = electrical watts
battery current is electrical watts divided by pack voltage
you can calculate the ohmic heating from motor current * motor current * winding resistance = wattage copper loss & ohmic motor heating
wind drag force in newtons is (1÷2) * 1.225 kg/m^3 fluid density of air * estimated frontal area in m^2 * (velocity in meters per second * velocity in meters per second) * estimated drag coefficient = wind drag force in newtons
wind drag power/wattage is wind drag force in newtons * meters per second = wind drag power/wattage
ignored is iron loss, esc loss, battery loss, drivetrain loss, and rolling resistance.