I did almost the same. Initially I had a 3v dcu psu plus ikea zigbee outlet, but in some rooms I have two fresheners and is was getting a bit overkill.
So now I convert them to 12v, and use a nodemcu close by (which does other things too), to power a relay. Note that I have a variety of daft projects around the home, and it made more sense to eventually replace the multiple dc units with one single high amps 12v psu with which I send around the entire house. Wherever I need a step down, I either use a step down dc unit (as in, inside the air wicks and inside my external 6v alarm box), or a 12v-5v-usb converter inside my back boxes for my multiple nodemcu's.