The sonoff wifi devices can be flashed with new firmware (they are just ESP wifi chips). I used the Tasmota firmware as was relatively easy to get going and supported MQTT to integrate with Home Assistant.
I installed a few sonoff relay devices behind standard light switches so can operate lights as normal but also remotely or automatically (this does require some mods to the units but plenty of help available on youtube). Limitations are multigang lights as units are too big to go in wall without more DIY
See here for all the info you need.
I am is the same state as Joe with a mix of RF433 switches (Livolo) which look nice and work well but are one way (no signal back to say the light is on - and the RF codes are not great).
My ideal situation would be a wifi version of the livolo switch without call back to China!
Cheers, Stuart (NZ)