It's a tough call for Luka though he needs to step up and play as the main alpha and part of that role is being in-charge in both sides but I agree it's a overwork for Luka, he needs someone to step up in their defensive side, he can bring the offense to explode but that's going to be a wasted efforts if they've fail to guard their opponents, still lots of game to play they have that enough time to adjust and be a two-way gunner so they'll be able not just score but also to bring that good stop limiting their opponents.
Not really that difficult, he was the alpha at Dallas too, and now he is going to be alpha at lakers as well. Sure for a while when he played with Lebron he wasn't the alpha, we could say that he was not taking orders neither, he wasn't some role player, but he wasn't the captain of the team neither, now he has to take that leadership role too now that Lebron is not playing and resting most of the season. But that doesn't mean Luka can't do it, he is good enough to make that work.
We will see Luka have a career year I am sure of it, of course that is only possible if he stays healthy too. I always found him a bit out of shape but because he can score and do what he needs to do, it never bothered anyone, same like Harden. If that causes any injuries, that's an issue.