Aside from Lumiose City and Lysandre, X&Y had the most forgettable OST. Even SwSh, objectively the worst games in the main series, had more bangers. Title of best OST goes to FireRed and LeafGreen, don't (You) me.
https://www.youtube.com/watch?v=LF_mzjhK6vU
https://www.youtube.com/watch?v=i649odAK7-M
https://www.youtube.com/watch?v=Jkd9Lv61oRk