Know that you’ll probably hate what you try first. Personally I say you shouldn’t use Pop_OS!, but its better than being scared of making a wrong choice. “distrohopping” is a great way to learn.
Being too attentative (distracted) to the speedometer is far more dangerous than the harm of going 5-9 mph over in many cases. And like mentioned earlier in tbe thread, many cars have a spedometer only accurate within 2-4 mph.