Cannot connect to server with increased height - server crashes

I was upgrading server from 19w39a and added datapack from https://github.com/onnowhere/examples/blob/58d50eb47c9ff42601860b3e53c13381dd8f3b66/negative_height.zip

First it crashed when loading world, when I am almost connected to it and when I reloaded chuncks becouse they did not render.