The difference between the two is different functional positioning.

Switch Raspberry Pi is a single-board computer mainly used for learning programming, building servers, etc. It was developed by the British Raspberry Pi Foundation.

It is often used as an educational tool, but is also used by hackers and enthusiasts for a variety of projects, including running game emulators.

Atmosphere is an open source project that provides operating systems and software for devices such as the Raspberry Pi. It aims to provide an easy-to-use, powerful and secure operating system to support a variety of Raspberry Pi applications.