Click here to see a Stream & Tech NOW video that explains 3 different ways of customising your device that you may want to experiment with if you like the way they work.
Click here to see another Stream & Tech NOW video that concentrates on how to get access to his site and install the alternate launcher mechanism. He mentions that this is not always straight forward and that you may need to restart the device and / or 'force close' other apps that may be running as exclusive access is required [temporarily] to ADB debugging feature.
Click here to see 9to5Google article "Android TV: Must-have apps for 2022 [Video]" for a Feb 2022 updated list.
Streamline Your Home Screen [limited]
You can use the built in settings to have "Apps Only" mode but while this looks neat you do lose the use of the microphone for the Google Assistant facility {except in Apps like the Play Store} which you may consider too high a price to pay.
Customise Your Home Screen [fully] with Wolf Launcher
Click here to jump straight to later section of a video by TechDoctorUK that shows you how to install this special launcher that lets you take complete control of the layout and content of your home screen. This includes losing all the ads, and getting some neat widgets, but without breaking the microphone.
Mix It Up
The Wolf Launcher [which is only available for the Chromecast with Google TV devices] and some others can be used in conjunction with the TechDoctorUK's Launcher Manager that lets you dynamically select your preferred interface, so nothing is lost and you can revert to using the standard Google TV layout whenever you want. Click here for a short clip about customising the Wolf interface.