BOTW has gotten kind of stale for me. There all too many shrines compared to dungeons and most of them are kinda boring. The story isn't really all that great and you have to run in circles across the entire map to get small parts of it, and combat at the end is just higher hp enemies and you can spam eat to heal which removes most of the challenge.
Xenoblade 2 has the story as its main draw that is pretty good and keeps you engaged for the most part. Would say that Xenoblade 1 is a better story but that's a different discussion. Combat slowly opens up which makes the early game be a bore but gets engaging when everything is unlocked. The core crystal thing is kinda stupid for a single player game but I understand the intent of making every run slightly different. But overall I would be more willing to play XC2 over BOTW.