Just to satisfy my curiosity, would you mind elaborating on this? Google Play Store tells me that I can’t install the Wyze app on my Google TV. I haven’t yet dug deep enough to see if it’s possible to install the app onto a Chromecast device, but I suspect that it isn’t. For the Wyze and other cameras that I’ve linked to Google Home, I usually just ask Assistant on a smart speaker to cast whichever camera I want to see at a given time.
After I read that, I tried the Screen Cast feature on three different Android devices, and only one of them (a lower-end tablet running Android Go) was able to cast to the Roku Express (the other two just didn’t see it, though they could see a Chromecast HD and other devices on the LAN). It worked really well, though! I was able to run the Wyze app on the tablet and see everything on the larger TV screen via the Roku, including doing a 4-camera group view in landscape mode. 