Koexygen isnt terminating Wow.exe, that is Daemonic that is doing that.
It is doing that as a protective caution since you are trying to inject into a version of WoW that isnt supported yet by Daemonic.
This is because you updated WoW before Daemonic had patched and added support for it.
A newbie mistake when using unlockers, you always need to wait until the unlocker is ready first!
Follow the discords "Daemonic-Updates" channel and you will know when it is ready.
Banno's post in Koexygen Terminates WoW.exe on launch bc version missmatch?? was marked as the answer