The influence of building a 1.5-meter-high wall on the terrace of the house on geomantic omen.

It doesn't matter if it doesn't affect the lighting. If you feel affected, you can open a small skylight and install a small window on it.

1.5m fence blocks the view, which is for safety reasons. From the perspective of geomantic omen, if the floor is high enough to not affect the lighting, it will not affect your home.

Finally, I suggest you take science as the basis and don't believe it too much.