Should work fine by just putting '-dev' in the launch options, no need to modify any files. You will know it works as a console should launch alongside the game that shows the logs. If you don't see that, it probably means the game doesn't recognise the launch option.

You could also potentially try verifying the games integrity but I doubt that will fix anything, I can't really give much more insight here.

I did verify game integrity and then put -dev in the console before making this topic to be thorough. I do see the console open when the game starts, but that doesn't give me the Dev options. None of the commands work, neither in Vanilla survival, nor in your mod.

That's why I made this topic. I'm wondering if other people have trouble getting this to work.

is it -dev or /dev?

same for me. -dev as start command works. but no commands are working ingame

In all my years of scrapping over never heard of the -dev thing and I can't find anything about it either...

Found a solution!

You need to find the SurvivalGame.lua file at this path
Example: \steam\steamapps\workshop\content\387990\"CUSTOM GAME ID"\Scripts\Game
We need to find: \steam\steamapps\workshop\content\387990\3238463364\Scripts\Game

Open SurvivalGame.lua with any text editor

Now we need to find:
if self.sv.saved.data and self.sv.saved.data.dev then
g_godMode = true
g_survivalDev = true
sm.log.info("Starting SurvivalGame in DEV mode")
end

Let's change it to this:
--if self.sv.saved.data and self.sv.saved.data.dev then
g_godMode = true
g_survivalDev = true
sm.log.info("Starting SurvivalGame in DEV mode")
--end

Now start the game, type /unlimited or /limited in chat

Voila