The Tegra X1 reduces its clock speed to around 307MHz when "undocked". This is why Zelda FPS rates range from 15-30 "mobile". Docked it is around the 770Mhz range. If SE had the option they would make the game play in docked mode only, as the poor FPS undocked would be horrible for the player and their party would likely suffer from it as well. However, if Nintendo Switch Policy states titles must be playable in Docked and Undocked mode, why would SE even bother.
Realize I do not know Nintendo's Switch Development Policies.