I have a new pixel 6 and a new ChromeCast with Google TV.
I want to hook it to a tv on my boat and may not have wifi but want to screen cast from my pixel 6 to the chromecast device (also was going to get a vizio chromecast tv). Articles talk about putting chromecast into guest mode from google home app but the instructions on line don't match up with my screen...and don't see options for guest mode.
I am happy to buy a different chromecast if that is an option. I am thinking I can also possibly get a usbc to hdmi cable and use that from my phone. I have dish anywhere app so last year when I had a samsung phone and samsung tv it just worked great with screen cast from the phone to tv with no extra devices/adapters/wifi or anything.
All Chromecast devices require a wifi network with full internet access at all time. Even when screen mirroring.
Guest Mode doesn't change that. Guest mode lets a phone that is not on the WiFi talk to the Chromecast but the Chromecast still needs WiFi and Internet.
Samsung may have a different kind of proprietary casting protocol that may may not require internet. I'm sorry, I do not know enough about theirs to be sure.