My solutions to hide defenses are:

A cliff. Dig a trench, flatten out one side, then use the cultivator to make it look natural again.
https://steamcommunity.com/sharedfiles/filedetails/?id=2532973343


Workbenches everywhere. Since workbenches stop spawning, I created a massive base area with strategically placed workbenches to stop all spawning within the base. I did place a low level, 1 stone piece high wall around the entire base to stop wanderers from wandering in. I also placed little stone huts along the wall that have a workbench inside it to increase the spawn protection beyond the walls. As long as you aren’t too close to the wall during a raid, then nothing will spawn. There simply is no available spawn point within the red raid circle.
https://steamcommunity.com/sharedfiles/filedetails/?id=2532973414

I did exploit this by creating a pit within the base that has no workbench cover. So if a raid does happen, then enemies will spawn in the pit and get stuck. They will despawn though once the area is reloaded.
https://steamcommunity.com/sharedfiles/filedetails/?id=2518693019