I'm amazed no one has suggested Chromecast. It just works. Click a button on your phone or laptop and the video or song you were listening to or want to listen to suddenly appears on the TV. Even grandparents seem to get it. Maybe Apple TV is a similar experience but Chromecast is as good as it gets
I know a lot of people seem to love Chromecast, but for some reason using a phone to control TV never made sense to me. I prefer the physical remote. And for sending screen to the TV, the quality was never good. Our Chromecast and the one included with TV haven’t been used for years.
However if you’ve used an AppleTV you realise that the Chromecast is actually a pretty terrible solution, compared to just having a device with apps.