They already have to optimize for docked/undocked modes separately anyway since it's rendering different resolutions using different hardware speeds depending on whether it's docked or not. There's already a mobile optimized hardware with the Switch Lite too, is it really that much of a stretch to make a dock-optimized version?

Besides, the Steam Deck has shown that even very demanding high end games designed without any consideration for mobile hardware can be sufficiently scaled down to run on mobile hardware (and mobile hardware has gotten powerful enough where the tradeoffs are tolerable).