On-demand water heaters – do they work?

One of the YouTube RV folks, don't remember which one, tackled this problem. The solution was to turn down the temperature at the water heater to about what you want in your shower, which makes sense, but isn't obvious. That way you only turn on the hot water, and that keeps the water heater from cycling on and off. If you want warmer water for doing dishes, turn it up to what temp you want, then turn it back down when you are done. I believe it was The Fit RV. He's very good at looking for solutions for RV problems.