they are the same universe
Sam exists in both games its just timeline is different a bit
after caesar got defeated he decided to go into full gambling and built a las vegum
and to full fill his militaristic desires he wanted to make gauls the main showcase of it
But they don't recognize Sam at the start of XXL2
Asterix and Obelix got amnesia
Druid made a potion for them and everyone else so they forget each other for the sake of their own safety since Sam is #1 wanted traitor of Empire
xxl2 has a lost spin off about all that
the game reintroduces us to him
however, Sam alludes to the game mechanics of XXL1
he also knows about the dimensions in AOG
so basically, he's just god and can travel freely between dimensions
guys i am telling you Sam is a time traveller
he is a genius scientist from future who got stuck in XXL and needs helemtz for his time machine to start to work
in xxl2 he gets used so much to the dimension that he decides to stay and becomes more advanced
in OG he does his first try in travelling around the dimensions but still prefers XXL dimension
he probably visited our dimension as well but couldnt stay anymore because it didnt feel the same
he jumps through dimensions and timelines to warn the Gauls whenever one of Caesar's plans is shaping up to actually work
can you imagine that he needs to guide every gauls
and has to pass through same shit over and over
Sam has seen some violence