Alcanbrad

Not necessarily IMO, pedaling introduces forces and torques throughout the bike, so it would indicate that it is related to putting power into the drivetrain. It could be drive train, it could be other.

Recording video with a selfie stick is an excellent suggestion. I once chased an annoying click and tried a usb voice recorder stuck in various places but it was difficult to get a lot of data points and quick feedback. I’ll remember this suggestion for the nest time.

Given the cadence, duration, and frequency of the noise, I am still stuck on the brakes. It sounds to me like a rotor is rubbing. Have you tried lightly squeezing each brake while pedaling during the noise and noticing if the sound changes? Squeeze lightly and slowly alternating front and back. If it’s a brake, you will hear a change.

I believe this is a ebike. Hub or mid drive? Does the sound change based upon the PAS setting? Have you tried riding without power longer than required to hear the noise to appear? Motors generate a lot of heat an have a large thermal mass which takes a while for the temperature to raise. Our front hub motor sounds different as it warms up. I would think that if it was the motor, the sound would be lower in frequency and more muted/muffled. You can try playing with the motor settings to see if changes in the motor characteristics affect the noise.

perhaps a picture or two of the bike would give something to look at and spur some thoughts.