The app supports up to 720p in handheld mode and up to 1080p when docked. It does not support 4K.
If you have Nintendo Parental Controls active, the YouTube app (rated "Teen") may be locked depending on your restriction level.
There is no official method to download YouTube videos directly through the Switch’s YouTube app. how to download youtube on nintendo switch
The YouTube application is a free download available through the official Nintendo digital storefront.
The Nintendo Switch operates on a proprietary operating system with strict sandboxing of applications. While the YouTube app from the Nintendo eShop allows streaming over Wi-Fi, the console lacks a native file system accessible to users for storing downloaded video files. This paper addresses three core questions: The app supports up to 720p in handheld
Navigate to the Search/Browse tab on the left sidebar. Type "YouTube" into the search bar and press the plus (+) button or select "Search".
Not viable.
From the console's Home menu, scroll down to the orange shopping bag icon and press A .