I am a university student connecting to a shared wifi network across all of campus. My pixel 4a gives me a notification saying I have shared controls with a smart TV on campus, I can adjust the volume and see what they are watching/playing ect... I can also cast to any device on the network. I understand this is a feature inside the app that makes it easier to create a smart home frame work. I have never set up a room or even use the Google home app. Is there a way to stop seeing/connecting to these devices on my phone? I have coworkers with pixel phones that are connected to the same network and do not have this issue. I have followed steps from google support to turn off media controls for cast devices but I still had shared controls 2 devices.
Any device connected to the same Wi-Fi network can cast to and control the cast media of Chromecasts connected to that Wi-Fi network, that is by design. It sounds like you're already aware, but follow the "Turn off Cast media control notifications on your phone" steps below. This won't stop you from being able to see and cast content but it will permanently turn off cast media control notifications from displaying on your phone.