I’m attempting to chromecast Zwift from my laptop to my TV but I cannot fined the chromecast icon
As far as I know it is not supported yet.
It does work however there is a couple of seconds lag. You need to open the google chrome browser and in the top right there is the Chromecast icon.
Click the icon and set the source to cast desktop. This will cast your entire desktop so as long as you have Zwift open it should mirror your laptop but as I say there is a couple of seconds of lag so if that annoys you then use a cable from your laptop to the TV.