Gain in current but not in voltage -transistor "voltage follower" set up
Just because 2 quantities are related by an equation does not make them the same. For example, F=ma relatesd force and acceleration by a fixed parameter, mass, but they are still distinct concepts. Ohm's law is not a general rule, Kirchoff's laws are more general and do not imply that current and voltage are thje same: apply them to more complicated circuits than a single resistor and you would see this. Ohm's law has little to do with amplifiers.  In the case of a voltage follwer, the output voltage is approximately the same as the input voltage but the available current is higher due to the current gain of the transistor.  As already noted, the input resistance of the voltage follower is much higher than the output resistance so Ohm's law does not apply since these resistances are different.