I still think what I had in mind could work. The biggest problem might be that the rice cookers are not designed to get over 100 degrees. The device could be damaged
I also could buy this device, which can do both:
https://www.reishunger.de/produkt/1422/digitaler-mini-reiskocher
but it's to expensive for me.
Persian rice cookers have just not at all the
function that they turn off when the water has evaporated.
But only a timer, which is not good for Asian cuisine.