MonumentAddons - Failed to compile: 'MonumentAddons.CustomSpawnGroup.Spawn(int)': cannot change access modifiers when overriding 'public' inherited member 'SpawnGroup.Spawn(int)' | Line: 8879, Pos: 37

the problem with protected override void Spawn(int numToSpawn) is related to changing the access level of the method, which is defined in the base class. The compilation error indicated that the Spawn(int) method in the base class has the public access modifier, and in your code it is declared as protected. I made the necessary edits, I hope you don't mind if I post the version I corrected here!

https://github.com/kut86/plugin

Same as you reported on another plugin I maintain here, the issue is your Oxide configuration. You need to enable the publicizer. You must have disabled it for some reason as it's enabled by default since many months back.

In oxide.config.json, set "Enable Publicizer": true.