I use my computer to stream video to the tv in my family's living room, and after upgrading to zorin os 16 pro, previously on windows 11, I can no longer do this with the hdmi cord that proved so handy. I also cannot do it on my admittedly older second monitor that I used to browse the web and discord without leaving a fullscreen game.
I have disabled secure boot, I have also updated all software and drivers, and cannot find another solution online to my specific problem. The displays dont show up at all, as if my hdmi cable wasnt connected at all, but worked just fine yesterday on windows 11.
I never used an HDMI cable as I plug to my TV with a VGA cable so I don't know how it is with an HDMI cable. Try doing these
open Software Center, click Extensions and check if under Hardware Drivers there are some drivers to download related to HDMI
hold Windows logo on your keyboard and press P to switch between showing both screens, only laptop screen, only external screen and merge screens, but never release Windows logo when you press P otherwise you close screen sharing mode switch function
check your laptop resolution, sometimes the external screen can't fit the laptop resolution, I had a OUT OF RANGE issue with mine
I don't think that your TV or your laptop don't detect each other, maybe a driver for the HDMI port misses.