Dex works if your TV and phone are on the same network. As I found out the hard way. TV was on netgear1 and the phone netgear2. Has to use netgear1 for the phone and everything worked a treat.
Hi @Johnpmac84 Dex connects wirelessly on Smart Tv's ,however works more effectively with Samsung Tv's released from 2019 onwards. As has already been explained phone and Tv need to be on the same network. In addition you cannot have the link to Windows turned on at the same time.