About Royer ZVS LC oscillator modification

I have a question about a modification I tried to make to a ZVS LC Royer oscillator. Basically to perform one experiment that requires hard-switching, I tried to implement a couple of mosfet drivers, the mosfets are two "IRFZ44N", and the drivers are two "TC4420", the operating frequency is of 2MHz. Because the input voltage must not exceed 5 volts, I added a couple of zener diodes with 4.7 volts of breakdown on the mosfet driver input, then connected the output directly to the mosfets gate. On the breadboard everything worked, despite being aware that it was probably not a good idea to try it there, given the high frequency, and considering it drops a lot of current even without load. But once I passed it on to a PCB, the situation got worse, maybe I should add a small value resistor between the driver output and the mosfet gate to limit the current better, and maybe prevent also some possible ringing? Could this solve the problem potentially?