@IosMess If you want to manage Matter devices from different brands with a specific app, you will need to have a Matter hub from the corresponding app brand. For example, an Amazon Echo is needed if you want to use Alexa app to manage Matter devices from different brands.
 

However from my research, it seems Philips doesn't release a Matter hub yet? In this case, the Kasa KS225 switch cannot be added and managed by the hue app.