Am I right in thinking that screen copying is only possible on activated devices?

I've owned the LG GX2, V20, G5 whose GX2 had a micro USB port for charging and an HDMI micro for video output and the V20, and the G5 had a USB-type video output c to HDMI. I have recently received the LG G7 or whatever it is called and it does not work anymore. I've read several articles that suggest that with the right combination cord / adapter, any Android could be reflected via HDMI on TV. I'm sure I already know the answer, I just want to be sure.; 3533870% 2F & psig = AOvVaw3iTFkpqfCgVxVKHKEUBXkH & ust = 1551124053191754 amp .html