A big factor is the number of cylinders and their arrangement, which affect the so called primary and secondary engine balance. A smaller single cylinder produces much more vibration than a way larger inline four with a 1-3-4-2 firing order.

I would assume though that phone cameras are damaged by higher frequency vibrations, a big component of which is speed and type of tyres/road condition

This is a big factor. My Husqvarna Vitpilen 401 is a single cylinder 373cc engine and boy does it vibrate. My Kawasaki Versys 650 is a two cylinder and the vibrations are barely noticeable even at red line or high speeds.

I have a single cyl bike that goes over 160mph and tries to wheelie out of your control at every chance. The vibration is way worse than a similar 4cyl. The more pistons, the less vibration. That is why luxury cars have been the homes of v12s and the like. Harmonics are more impactful inside the engine. Uneven firing of the cylinder is actually a feature to maintain traction in sport bikes, look up 'big bang firing order' for an interesting rabbit hole.