Bethesda has updated the FAQ for Wolfenstein: Youngblood, and in doing so confirmed that the game will not have a cartridge version on Switch. The title will only be available digitally and the physical version contains a digital download code without an actual cartridge.
Will the Nintendo Switch version be digital only?
The Nintendo Switch version of Wolfenstein: Youngblood will be available digitally. The physical version of Wolfenstein: Youngblood will be a digital download code in the box with no game cartridge. A download will be required to play the game.
Will a download be required to play Wolfenstein: Youngblood on Nintendo Switch?
A download is required to play Wolfenstein: Youngblood on Nintendo Switch, whether you purchase the game digitally or physically at retail.