as i am trying to make my zombies map, zombies are not spawning due to "they are out of the world" i checked the coordenates and as you see in the pictures they are below the natural 30,000,000 limit. This was also happening when i was trying to use /setblock and /fill but i did not get screenshots of those.

as you can see with a closer look coordenates are set between (x)1000 - 1500 (y)4-5 or (z) 1000 - 1500

not 30,000,000 to -30,000,000

i am thinking it may be due to chunks not loaded