/reload doesn't work in Hardcore maode

I am able to load certain datapacks since they need me to use the /reload command. It worked before but now they are unable to load.
This is a data pack that needs the /reload command to work. https://tryashtar.github.io/shulker-preview/
f3+t does not work
I am unable to reload. In other worlds I can type the command /reload but it is not working in my Hardcore world.