Lezyne makes some nice ebike lights. They do have a proper GoPro mounting flange but also have a system to mount to the front of the stem with some posts that go under two of the face plate bolts. Here are links to two good options:

https://www.amazon.com/dp/B07CZFH892
https://www.amazon.com/dp/B083WNFCGQ

But I'm not 10$ sure if they come with a bosch connector on the end of the cable. So you might need something like this and a bit of soldering. https://www.amazon.com/dp/B01A5Z10XA