I think you can also power the console off completely and still charge it.

This is not an official Nintendo source, but:

When your Switch is in sleep mode, it still consumes a small amount of power. This is necessary to keep the system ready to wake up instantly and maintain processes like downloading software updates. However, the power draw is minimal, especially compared to running a game. When completely turned off, the Switch consumes virtually no power. This theoretically minimizes stress on the battery during charging.

https://cyberpost.co/should-i-turn-off-my-nintendo-switch-while-charging/