I already love the games, so that's promising.

The manga tends to outshine the games, at times.

For any arc, not just X and Y

Story-wise I can see why. I haven't read them but I've done a lot of research on them, and given that they're entirely story focused, I'd imagine that they'd expand on the characters more.

I've also heard that they're notably darker than the games and anime, which is interesting.

Very much. There are much darker tones in the manga compared to the games and anime. Lots of angst too

I wish there was a sword n shield

Otherwise the like out of order i read (5,6,7 then d and peral, all i read) lol is great

I think there is a Sword and Shield manga

My second favorite manga series.

I've only read the Kanto arc and some of the Johto arc. I've enjoyed what I've read

The Kanto arcs were good. That set technically had two different arcs, including the Yellow one