Connecting Xbox, Apple TV and sound output via Airplay

1. You can’t daisy-chain HDMI devices at will; some Xbox consoles have HDMI-in; but that is not for 4K. It is intended for (older) cable and satellite boxes, not for advanced media players. Your Apple TV and Xbox will need each their own HDMI connection to the TV. If you do not wish to swap the HDMI cable plug constantly, nor use an HDMI Switch, then plug both devices to separate HDMI ports on the TV.
2. If you wish to use HomePod speakers [1] [2] also for video content not-from-Apple TV, then you may choose to have Apple TV 4K (2nd generation or later) be the “audio unit” that uses the eARC connection. (Other AirPlay-enabled speakers are available to Apple TV, but the TV and other TV-connected devices can’t use this eARC function by Apple TV.) Use HDMI ARC or eARC with your Apple TV 4K - Apple Support.
3. An HDMI switch uses just one of the connected input devices. When using Xbox, the Apple TV wouldn’t be used for any function, including audio to HomePods. Try avoiding HDMI Switches if you have enough HDMI-in ports available.
4. Some users prefer a setup with an AV receiver. Then there could be one connection to the TV, and have all the other HDMI devices connect to the AV receiver, like a hub. Popular with 5.1 or higher speaker setups. Also a different price range.

I understand that unmounting a TV can be a hassle, if that is needed to reach the HDMI ports, but alternatives are probably worse, imho.