WINE runs them fine, so there’s a limited return for Blizzard to do a native port.

Officially supporting the Linux platform does not mean doing a native port. Look in example what Marvel Rivals does. They do support Linux, with official statements and with bug fixes related to Linux (they even specifically mentioned a specific bug fix for Bazzite in one of their recent patch notes). The game runs through Proton. Blizzard / Xbox could do the same here.