Just some loose thoughts from a person with limited knowledge on wall assemblies but a painfully large amount of knowledge on clash detection/visualization strategies:
Dynamo can retrieve wall information in a number of ways: you can GetLocation which will pull the centerline that generates the wall assembly, you can get the element geometry which will get the physical geometry of the assembly in a way that's interactable with raybouncing, you can get the vector that determines which direction an assembly with an 'exterior' face points, and you can get a whole bunch of other stuff I'm sure.
You probably need to make the distinction between if you care about corners that are generated by only exterior-assembly walls, one exterior/one interior wall, and only interior walls. I don't know what you're using this workflow for so I'm not going to make that assumption for you. You also probably need to distinguish exactly what a corner 'means' for your workflow: if I have a multistory apartment do the corners of each floor matter? Do the corners of a mechanical penthouse on a roof count? Or is all of this corner identification projecting to a flat plane so floors don't matter for the topic?
If you make that distinction, you can use the line geometry from GetLocation as a low-resource way to collect a list of locations/wall elements to check for corners. You probably want to take the list of intersections and see which ones are generated using 'only' endpoints of lines, or within a % distance from endpoints in case of bad modelling. A 'cross' intersection is likely not a corner candidate, a 'tee' intersection is also not likely a corner candidate. An exception would be if you're using that wall assembly and pulling it inside to form column covers (not great modelling but I've seen it done).
Once you finish your simple intersection check and simple filter to reduce the number of locations to investigate, you can render the geometry of those specific elements to try and get outside vs inside corners.Naturally, this gets more complex if you look at multiple levels, if you look at complex wall assemblies with thickness/material variations based on height, etc....
With a more clearly defined intent and set of assumptions for the wall assemblies, we can isolate portions of the workflow and discuss node/package options.
And to reiterate what @RDAOU was saying, you need to be more specific to receive support on the Dynamobim forums. Same as here, it's all users supporting each other and people are generally not going to create the script from scratch for you. If you can clearly describe your intent and then break down the intent into steps (showing that you just don't know what nodes/packages to use), you'll get far more traction.
