The whole spawntables and jargon surrounding it is quite new to me and a bit puzzling but I think I understand. I would like to edit an existing map's spawntable to add custom things to it for a better experience with my friends and I.

However, after scouring the web and several discussions and forums I can't get a clear answer for my question:
How would I go about editing an existing map's (downloaded from the workshop) spawntables without the obvious route of copying map, accessing it in the editor, applying edits, saving, and then reuploading it to the workshop. I would like to avoid that route if possible but if it's the only way then I suppose I will have to do that.

I've made a copy and unlocked it to be edited in the editor and I see that the map has its own set spawntables which I think some don't appear to be imported from the official maps. I want to particularly adjust/add loot to zombies as well as vehicles. Again, the only option I can see right now is just doing it right here in the editor and reuploading the map to the workshop so I can set it in my server.