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.
https://www.google.com/url?sa=i&source=web&cd=&ved=2ahUKEwi51efCkdXgAhVOgp4KHTaXCQAQzpw; 3533870% 2F & psig = AOvVaw3iTFkpqfCgVxVKHKEUBXkH & ust = 1551124053191754
http://www.google.com/amp/s/www.techhive.com/article/3268756/streaming-hardware/how-to-connect-your-android-phone-or-tablet-to-your-hdtv amp .html