Is there such thing as automatic hot cold water mixing valve?

We have a shower that is being used multiple times throughout the day. For each use the target temperature is always ~30C. Unfortunately, the water in hot water pipe tends to cool down if someone was not using shower for longer time. If this happens, then the next person using the shower have to either:

1. start at 100% hot water and 0% cold water. And drain the cooled down water from pipes. Only then ramp up intake of cold water. OR
2. leave the shower to previous setting and drain/waste even more water because cold intake would be delivering water while the hot water temperature is still ramping up.

I was wondering if there is a valve, that I could preset to specific target temperature and it would automatically intake only hot water until the egress water temperature reaches the target temperature. Once target temperature reached, then it would start to mix the cold water so that the egress water temperature would not go over the preset temperature. How is such valve called in English?

Also, it may be a big problem for us if the temperature ever gets too hot. If such valve exists is it fool proof not to go over the target temperature?

The main goal here is to save water and reduce time that person has to wait in the shower for target temperature to be reached. While not mandatory, perhaps a digital screen with two buttons plus and minus to fine tune temperature would be a great plus too.