One thing I haven’t seen mentioned is how iOS 15 took away the Apple TV remote app, and you now have to slide down Control Center to then click the remote. If this extra step annoys you (parents who’ve had to hide the glass backed remote out of their children’s reach will know what I mean), you can use shortcuts to launch the remote app from a single click once again.
Launch shortcuts, add a new shortcut, search for “Show remote for” and then select the one which says “Show remote for [apple tv]”. Next, click on the blue [apple tv] link and select the specific Apple TV you want to control and you’re done. You don’t get exactly the same icon, but there’s probably an emoji close enough that suits what you like. You can also set the main background colour and give it a name (“ATV Remote” with the grey background is what I used). Voila - your Apple TV remote app is back.