So I downloaded the WoTLK Mac client, followed the download guide (no install) and now when I run World Of Warcraft (through Contents > MacOS > World Of Warcraft) it opens the terminal and never launches. This is the failed text that I think is causing the failure:
Assertion Failed!
App: /Applications/World of Warcraft 3.3.5a (no install)/WOTLK/World of Warcraft.app
File: (unknown)
Line: 0
Error Code: 0x85100079
Time: 2019-05-27 17.04.21 CEST
Assertion: DBFilesClient\Achievement_Criteria.dbc has wrong number of columns (found 28, expected 31)