DFG
Speaking for Zurich area, rush hour is around 06:30 to 08:30 and 16:30 and 18:30,
however it hardly affects the departure times. If there’s a delay, it’s mostly maybe +1 to +3 minutes, sometimes around 5, rarely 10+ minutes. In Zurich city, it still can happen that tramways or buses are 1-2 minutes too early during rush hour!
Buses often have their dedicated lanes on the streets, and the drivers can directly prioritize traffic lights for them (same applies for tramways). This reduces the impact of traffic jams caused by private traffic.
Departures of S-Trains may be delayed 1-3 minutes because of the passenger masses, however such delays are often reduced or caught up when reaching the destination.
You’d rather notice that the trains, tramways and buses are quite full during those times.