This is largely solved by infrastructure as well, although it might perhaps be a bit tricky to visualize it if you haven't been in that situation before. As a cyclist, I have no interest in getting on a sidewalk because bike roads are much better. Sidewalks are often bumpy, can have high curbs, and as you mentioned are crowded by people randomly walking around. Bike roads have none of that, so it's objectively better to ride there. To a lesser extent the same holds for car roads. On bike roads, your light goes green first, the ride is smoother, etc. All of the above means that as a cyclist, there's very good incentives for me to stay on the bike road.

Police does sometimes pick off cyclists who are on their phone and whatnot, but outside of that, it is a very self-regulating system. It's also fuelled by the society, teaching your kids how to behave as a cyclist is a very visible part of upbringing.