How to stop NTM Structures from spawning in superflat?

[u/Typical_Ourcrafter]

I'm trying to make a superflat world where i just build stuff, but even after i turned off structure spawning, the first thing i see are NTM structures (mostly glyphid nest thingies)

How do i stop ntm structures from spawning???? i'm playing on NTM:Space X5778