Seems like something may be wrong with sound alias files or something not sure. I'd be willing to pay someone on cash app to help fix this at this point.
Any sounds from custom weapons, sounds triggers for custom music, none of it functions.
 
^1ERROR: unable to load file 'sound/zone//zm_zombiez.all.alias.sz'
  csv:zone_source/zm_zombiez.zone
^1ERROR: sound aliases failed to load
  csv:zone_source/zm_zombiez.zone

there is a slash to much and you need a c at the end. u have to write sound/zone/zm_zombiez.all.alias.szc not sound/zone//zm_zombiez.all.alias.sz its .szc not .sz