Iron farm isn't working still🤷

I've been testing iron farms for 1.20 bedrock and none of them are working, I'm pretty upset about it because iron is one of the most needed resources and I need a lot of hoppers for other farms. I have 20 terrified villagers and 3 zombies in one farm, 3 villagers and 1 zombie in another and 3 villagers and 1 zombie in the last one. None of them are working despite being on hard mode and switching back to survival. Its the 3 most recent farms and I know I built them correctly, nothing spawning in.