World is full of quests and unrevealed secrets...
But u had worm in the head, so you must hurry to solve your main quest - win the race before worm transforms you into ktulhu-tyan
So there is a lot of XP that you won't get. btw in tutorial chapter in Avernus u can kill all demons - they all worth 50xp... and imps and all dying bodies for 1xp
And there after u can gather a group without interaction with dying Illitid. Feed yourself to him and fight him 36/58(???)hp. This is pretty tough, it worth me 2 rez scrolls and a lot of mindgaming but it is 26xp (not sure about numbers here)
I am very dissapointed that dialoging instead of fighting gives you less XP... even killing unconscious (after special attack, that "stuns") has NO XP reward
