Hi, if you are having issues trying to connect the Chromecast to the WiFi my recommendation is to make sure that the WiFi security encryption is compatible with the wpa2/wpa3 mixed personal default setup that comes with the router, make sure that the Chromecast has its later software update as well, if the issue is that you can not connect to the internet I recommend to test internet access with other devices and if they work please check with the Chromecast manufacturers if there are some ports to open in the G34 or any possible workaround to resolve the issue.

It’s definitely a hassle to change your router.  You’re basically having to setup your entire ecosystem.  First thing to make sure is that your devices are connected to your router.   Chances are good that all your devices in the network might get a different IP address from the new router.  You might need to setup your printer again on your PC.  Hopefully someone else can chime in with Chromecast issue.