

OK, assuming your switch is also smart
Option 1: long-press/double function turns on both light and fan, that triggers an “I am going to shower” 5 minute delay where a humidity sensor senses when it is over and keeps the fan on until humidity is stabilized with the rest of the house.
Option 2: get a smart flow meter instead of a smart valve. Then you have useful statistics for shower water usage in addition to an instantaneous status. This has the side effect of the mood lighting turning on “late”
Option 3: get one or make an esphome + LD2410S on battery or plugged in close by, nobody goes in the shower for more than like 10 seconds without showering
Option 4: Time of Flight sensor outside of the shower pointing in to tell when the door/curtain is closed. If the ToF sensor is (for example) between 1.1m and 1.2m, the door/curtain is closed













Why does every one of these cartoonishly evil companies have a cartoonishly evil name.