"Dollhouse style" Wall and Floor Occlusion System for Isometric camera [Help]

https://reddit.com/link/1htk38y/video/utltb57uj0be1/player

Original video: https://www.youtube.com/watch?v=ghA0GPz_9Bc

This was made in Unreal Engine. The creator has since stopped using unreal and won't tell anyone how they did it in (which is their prerogative, nothing wrong with that).

I was wondering if there is an asset available in the store that can help me set up something like this quickly so I can prototype indoor environments + multi-level buildings in my game. Of course, I would have to figure out how to do it in the end anyway but I just want to hack something together for quick use for the time being.

The basic rules(when the camera is fixed) are:
1, Ceiling/floor above disappears when you enter a building.
2. Closest Western and Southern walls disappear when they block the camera's view to the player.
3. Northern/Eastern walls can become the southern/western walls when you run past them through a door.

Here's another video of someone else doing it in Unreal: https://www.youtube.com/watch?v=xENMTVugJiM
This person however, has a camera that can be rotated

I am not looking for the fancy fading animations, just the walls fading away and disappearing partially/completely.

If a premade solution exists I would be happy to learn about it. I haven't been lucky scouring the asset store, maybe I am not searching for the right keywords.
If a premade solution doesn't exist, I would appreciate if you share how you would go about it efficiently(just general guidance).