I assume since you are on this forum it is for mountain biking. Which GoPro? Regardless, Chest mount is number 1 IMO. Spare battery as well. If you are getting one of the older ones without stabilization, you will need a gimbal. Some people even say the built in image stabilization is not enough, but it is fine for the type of riding I do and I have no visions of making a living on YouTube or on my bike
Here is some funny guidance on how to make a video edit.
Chest mount on a GoPro Hero 7 or newer, or a GoPro Max. I’ve tested on a 5, 7, and a Max. The video directly off of the 7 and Max are stable enough to used directly off of the camera. I currently use a Max, and use it either in “Hero Mode” (using only one of the cameras) on my chest, or in 360 mode on a selfie stick, stuck into my camelbak, with the camera positioned just above my head. Both options work great, but they have a very different feel to them.
If you are primarily concerned with safety and reporting irresponsible drivers there is a product for road cyclists called CYCLIQ. Because a GoPro tape camera is not going to have a very long battery for capturing everything that On a multi hour ride
I agree with @iliketexmex – GoPro batteries tend to last around 45 minutes or so of actual recording, so if you’re going for a long ride where you want to document your ride for the sake of safety, then Cycliq cameras are a great choice.
I use a Mobius camera to do exactly what you described. It’s in no way a GOPro, but it does a great job at 1080p. It’s small and will capture any event with clear video, that you can zoom in on and read the license plate. I saw a Youtube video about one. The link is below.