For sure, if you can guarantee 60Hz, then frame hopping will be better, due to 'aliasing' associated with the first method (sometimes you will get perfect 1/3 updates, sometimes you will get 1 /4 updates doe to floating point drift).
Then you can also have options for 30Hz, 15Hz, 12Hz, 10Hz, 12Hz, ... (1/3, 1/4, 1/5, 1/6, ). A reason why '60' is a nice number to have.
Professionally, the first method is often used, with maybe some rounding error to compensate for round off errors and frame aliasing. Even sometimes the network tick runs in a separate thread.
Se second advantage, is that you can guarantee the frame timestep (so, each network tick will be exactly 20Hz, or considering to be exact), thus removing the need to implicitly indicate timing (you can measure time using the packet sqn, for example).
Sometimes, the problem of aliasing is not always such a big deal tbh. It depends how things work for you.