However, if the GM makes rules and alters the world so much that the players are unhappy with it, the players will go find another GM.
Again, we're here making suggestions. If Larian doesn't listen to our suggestions then that's Larian's call and I respect it.
But until Larian says, "Listen guys. We're not going to make this more like D&D and we don't give a flying rats behind about making it cohesive with the FR lore and world," I'm going to keep suggesting that Larian should make the game more like D&D 5e with more cohesion in the story, dialogue, lore, etc.
Right now, the game doesn't make logical sense in many, many ways, and that's a problem for a lot of people as is evident by the numerous, numerous postings that you'll find all over this forum site, reddit, Steam, etc. Yes, there are lots of people who are also like, "No! Larian! We love the game as is! Don't change it at all!" I'm not saying there isn't.
But that doesn't matter. I'm going to continue to relentlessly call for more D&D 5e rules and stats and other elements that will make the game more like a true D&D world and more like a Baldur's Gate sequel because I'm hoping that those who are in my camp are the majority over those who are in the opposing camp.
Isn't that what you're ultimately doing?
Maybe he is just not a typical specimen of his race and not only too proud but also an arrogant idiot. That is in no way lore or rulebreaking. We humans also have quite a lot of them, also in interesting positions where normal thinking people simply cannot understand how the hell they got there...
On the fact that larian needs to adhere more to the 5e ruleset i totally agree with you. Imo opinion too many homebrew rules can really ruin it. Shove/jump beeing a prime example. The kithrak behavior is a lore thing that does not sit well with you since it is idiotic behavior. Thats how i understood it.
Lorewise i am not sure if i can agree with you since "true D&D" lies a lot in the eye of the beholder. If you are as much a fan as i am you certainly have read novels too. Every author has his/her own perspective. There are some that i hate and others like and vice versa. I only hope that they do not contradict each other too much.
But i like that you fight for what you think D&D should look like so that in the end we may get larian to change it so that most players find it agreeable.