That’s because the issue isn’t the launcher itself, it’s with Blizzard’s authentication servers. Whether you use the launcher or not, you still have to be able to authenticate to be able to play…
I dont have that game installed, but it should work fine. Just locate the 64bit exe or the 32bit exe game launcher and create a new shortcut then add -launch to the end.
If anyone else is trying to swap to Asia, you can do the tip above, then in options in the game change region. This crashed a couple times but I’m in Asia new season now