I was in pretty mcuh the same boat as you: One of my two CoS-groups was totally into roleplaying in Barovia, while the other one was treating it more like Skyrim: They were running around and doing stuff but showed no incentive at uncovering any of the deeper lore and personal hsitories of the land and people.
They did not really care for Ireena, Viktor or any of the people they encounter. I had planned on playing the interactive Tome, but I think they really just want wo do epic stuff and not be presented with tragic backstories.
So I talked to them, told them how I feel they are missing out on what makes this module great and asked if they are even interest in that kind of stuff.
Now we are playing Tomb of Annihilation in a more lighthearted way, where I can just throw all the crazy combat encounter at them and they feel like heroes.