Personally, I suspect Light/Dark is more a matter of how he resolves matters in pursuit of his core priorities rather than what those priorities are. The fact those choices haven't changed core aspects otherwise so far hints that it's unlikely to fundamentally alter them, though perhaps that'll change later on.But how do you fit that with the "dark path" - I'm becoming convinced that that is the way to go with this one because I don't "like" any of the others - mainly because I don't think the writing has earned it. Other than fawning over the MC most of the Li seem almost entirely devoid of personality, or at least I don't find them interesting as characters on their own merits.
As an example, perhaps you can become a forgiving protector or a ruthless protector. Or that desire to protect can perhaps twist into a desire to control (to protect people from themselves, for example) if you get corrupted by power. But those changes aren't likely to strongly manifest until much later. At the moment, the impacts of Light/Dark will likely be more restricted.
Either way, I don't see him not caring about those things.