I like the headcanon of like... him being really handy with things? Like, he'd want to understand things because he hates feeling stupid, but he also doesn't do great with book-learning (and would end up getting frustrated because of it) and would be more hands-on with things? Like, he'd struggle with the computer or smartphone until he understood it inside and out. Like, not even just 'well I hit this button and then it works' (like he is in Kiseki because the differences in timelines is more accepted amongst people in game) and more 'no Merlin, this page can be displayed because of this-and-that because the so-and-so is connected to the blah-blhah-blah).
But that doesn't really show-up in game because he feels less pressure to understand it all RIGHT AWAY because there are so many different people from different times and worlds. So it's more like... he has a cursory understanding instead.
And also as what's been shown in game: he would really like sweet things. Not OVERLY sweet things cause he's just not used to that level of sweetness, but kind of 'this is a sweet treat' thing (like cupcakes or fruity drinks) he'd really end up enjoying.
Stealing the question I gave Celen with: How is Aramis feeling about Jamie, in regards to his own canon developments and his own level of 'closeness' with her?