I have this game object I made with probuilder:

It’s only one game object. No child or whatever.
I need it to be trigger in order to work with my purpose.
But the only way to flag it as trigger is to flag the mesh as convex. So the trigger area would look like this:

Here the trigger area goes over the corner so it doesn’t work as I want.
The other option is to make 2 cube colliders but that makes 2 trigger areas.
Is there a way to make just 1 trigger area for the whole game object that doesn’t go outside its vertices?