Bosch cargo motor making strange noise

I’m decently handy with bike maintenance, but this packster 70 is my first electric bike and so I have zero experience with the Bosch motor (and therefor hesitant to mess with it).

I’ve ridden it quite a bit in the 4 months since purchasing it, but the noise in question has seemed to get worse in recent weeks.

The video posted here is with the motor off, riding on a flat road and not putting much pressure down on the pedals. When I accelerate hard the noise goes away, and it’s most present when I reach the 18-20mph speed where the motor stops assisting.

Any ideas? (Also please let me know if there’s a better sub to raise this question on)