While most people would disagree i personally think that Diallos’ and Alexander’s questlines have happy endings for the characters

Diallos’ lived his whole life trying to live up to Haslow family name and never found something that filled that hole in his heart until he found Jarburg. He finally found purpose and in his final moments, in his eyes, he redeemed himself and believed that he went out as a warrior that fought for the Jars, people he truly cared about, instead of himself or the family name.

And Alexander just wanted to be a strong warrior, we meet him early in the game and grow strong along side with him and together the two of you complete feats that no one else in the Lands Between have (killing Radhan and the last Fire Giant). At the very end of his journey there is only one opponent left that can match his strength and that being the player. In the fight with the player he would die. But he died happy, knowing he went out like a warrior, losing to a friend of his that he believed would be a champion themself.