Tap Tempo Metronome drifts (ESP32 C3 supermini)

[Paul_KD7HB]

@c4mpid311i

For example, if I put another tap tempo metronome side by side, they start syncing but after some seconds I start hearing the difference. What could it be?

That is the real world, my friend. The internal clocks of the two ESP board are not IDENTICAL and their frequency drifting with temperature changes is not identical.