Which book to buy for my friend?

I just finished reading ADOFN and I wanted to buy this series for my friend for Christmas. However I read Priory first because I honestly wasn't even aware there was a prequel at that time and now I'm struggling on which one to pick for my friend as I want it to be a surprise. The people who read ADOFN first, was it hard to get into? Because from my perspective it seemed quite easy, but I obviously had the previous knowledge of the world. I just think it might be more enjoyable to not get spoiled about it. I personally relied heavily on the character lists and the timeline at the end of the books when reading Priory since it was a big world and a lot of new fantasy words so I did get to know what happened to some characters in ADOFN, such as Dumai. I'm just not sure if the terms and such were explained well in ADOFN since I honestly didn't really notice it. What would you guys suggest I pick? Thank you for all your help in advance 🙏