how to prevent players from being able to place locks on doors

If you mean that you are spawning additional doors at monuments, and players are able to place locks on them, that's probably because you are spawning prefabs that happen to be player-deployable doors. If you spawn doors that normally appear at monuments, you might not have this problem. If you really need to spawn the types of doors that are lockable, I would have to explicitly add functionality to prevent locking them.

The only use I have for this situation is a sheet metal door placed in outpost with a custom steam skin and often of times players come up and place locks on the doors preventing players from accessing an area that theyre meant to have access too without restriction.

I've pushed a change to the plugin's GitHub repo which should disable spawned doors from being locked. Can you test it?

https://github.com/WheteThunger/MonumentAddons

Yes! from my testing it does work !Thank you so much !