Modding dino stat change like Gigas - Higher wild, nerfed when tamed. Is it possible?

you can just stop those from spawning at all. Maybe the simplest way to solve the problem? This is easily done if you using ASM http://arkservermanager.freeforums.net/
If not it’s probably something you have to type in the .ini, or perhaps your server hosting company has it’s own GUI for it?

You could even replace their spawns with a different dino so something will fill their spot. Also, maybe making them none tamable is a better solution for you? I’m sure there is plenty of info on how to do all of the thing that have been suggested with a quick google.