Blueprint/Code driven landscape visibility?

Just projecting the opacity to zero at an arbitrary point would suffice for me.
Was trying to achieve it with virtual textures, but I can’t make any sense of it :(.

Why would the landscape be poor? So instead of landscape what should be used? Just a plane with 1000 x 1000 division and deformed with noise? I did this but it renders insanely slow compared to just the world landscape.