I have 10 KS220M dimmer switches in my house as well as 20 plus other tplink devices.  For months I have had my KS220 devices become unresponsive and randomly turn on.  I seem to have solved all these issues by using IP MAC binding on my ASUS router.  This forces the IP address to be the same every time the device connects to the router despite using DHCP.  I have a Home Assistant server and use Google Home and everything works with the tplink devices.  Nothing to do with firmware.  Most routers have IP binding or IP reservation.  Just Google " IP binding" and your router make for instructions and YouTube videos.  I was getting to the point of scrapping my tplink devices because this was so irritating but this solution has fixed everything.  Hope it helps.