How can I cull my prefabs that aren't inside the 2D Camera View in Unity

Question

I'm working on replicating the game "Deepworld". I setup world gen using array maps and some special logic. I'm creating hundreds of objects in seconds. This destroys performance.

Even hitting the play button takes a while, and it's pretty hard to "exit" play mode, as it's basically 1 fps.

How should I go about culling everything not in the camera view. I don't understand any logic around the camera's view within C#.

If I knew more about how I could access the actual location and size of the camera's view, I could probably do something along these lines.

... {
    for (int y = 0; y < height; y++) {
        Vector3 pos = new Vector3(-width / 2 + x + 0.5f, objectHolder.transform.position.y, -height / 2 + y + 0.5f);
    
        // Imaginary If Conditions Ahead

        if (pos.x <= CameraViewMaxX && pos.x >= CameraViewMinX && pos.y <= CameraViewMaxY && pos.y >= CameraViewMinY) {
            Gizmos.color = (map[x, y] == 1)? Color.white : Color.clear;
            Gizmos.DrawCube(pos, Vector3.one);
            if (map[x, y] == 0) {
                Instantiate(block, pos, objectHolder.transform.rotation);
            }
        }

        // Back to Normal
    }
}

I don't know what direction to go in, and I don't know how to physically implement this into my game.

I know that I'm only supposed to load blocks in the view, like Terraria or Deepworld. That's the only reason those games run smoothly. It's because of the culling.