Setup Chromecast and stream to your TV - Google Store

Google Product Forums - Google Search Amanda, what you're describing works for me. Once I set up (using the Google Home app on another device) the Chromecast to be on my hotspot's wifi, I can cast from the phone that has the hotspot. The Chromecast stays configured to the hotspot's wifi until otherwise reconfigured. How to use Chromecast without Wi-Fi: Making the most of Jul 19, 2020

The Google Home app will walk you through the steps to set up your Chromecast device. This includes Chromecast and Chromecast Ultra. If you've already set up your Chromecast on a mobile device, you don't need to set it up again on a different mobile device if all devices are on the same Wi-Fi network.

How to Use Google Chromecast: A 5-Minute Setup Guide

Google Home - Apps on Google Play

Change the Wi-Fi network of Chromecast or - Google Help Make sure your mobile device or tablet is connected to the same Wi-Fi as your Chromecast device. Open the Google Home app . Tap your device. At the top right corner, tap Settings Wi-Fi Forget this Set up your Chromecast device - Android - Chromecast Help