I made this mod using an ai platform called Cursor. It did all the coding, I just gave feedback and told it what to do.
This mod makes zombies spawn over time, instead of normal spawns from the beginning. It is better played with a mod that increases zombie spawns. And played in a zombie apocalypse modpack. Zombies will now spawn starting a much less and over 20 Minecraft days (By default, but very configurable with: /day, /spawns, and more.) comming up to normal spawns. Players can use /spawnincreasecountdown to see how long untill the next spawn rate increase. There are also messages in chat notifying players when spawns are increasing.