The pitch maps of Wirtz is not too dissimilar to Ozil or even De Bruyne. Attacking midfielders tend to occupy spaces on the wings at times in order to influence the game from there. It's not the same as a winger though, who usually stay on the wing and rarely come inside.
Wirtz doesn't play out of position because of Musiala, it's because Nagelsman preferred 3 central midfielders (8's or 6's) to having a pure attacking midfielder in the Euros. There's also a distinct lack of RW's so Wirtz plays there instead. That being said, even in those matches as a RW, he's played centrally a lot more than actually on the wing. Him, Musiala and Havertz have been great as a front 3 with a lot of rotation.
Wirtz and Musiala van definitely play together, with one as a CAM and the other as a LW, both rotating positions and therefore having the freedom to play around one another.
Given that you don't think Wirtz can play as a CAM, you would think he won't be able to play well in any team other than United since no other big team plays a formation similar to Leverkusen?