I think it's likely that the golem spawning area is too far below the villagers.
If I'm understanding the Wiki correctly the golems can only spawn up to 3 blocks above or below the villagers.
(The phrasing in the Wiki is confusing though.)
Are the villagers using the beds and workstations?
If not they won't be able to spawn golems.
They have to see a zombie some of the time so they panic and decide they need a golem but they need time without seeing the zombie in order to use the beds and workstations.
The villager mechanics have changed often between 1.14 and 1.14.4 so I wouldn't trust a video from an earlier update than I was playing in.
My iron farm is not working for some reason idk why?
Can you please help.
I made it in one chunk.
EDIT; I have seen iron golem spawning mechanics from this video
I think it's likely that the golem spawning area is too far below the villagers.
If I'm understanding the Wiki correctly the golems can only spawn up to 3 blocks above or below the villagers.
(The phrasing in the Wiki is confusing though.)
Are the villagers using the beds and workstations?
If not they won't be able to spawn golems.
They have to see a zombie some of the time so they panic and decide they need a golem but they need time without seeing the zombie in order to use the beds and workstations.
The villager mechanics have changed often between 1.14 and 1.14.4 so I wouldn't trust a video from an earlier update than I was playing in.
Just testing.
I fixed it.
I saw that Iron Golems cannot spawn in water and I made a same design.
Iron Golems can spawn far away from villagers. It does not have to do anything with 3 block thing.
And they spended some time before seeing the zombie.