I have included their great backpack mod in my worlds and wanted to use a data pack to change the recipe for the backpack (standart).

1. In my singleplayer-world, the recipe didn't work until I created it in a separate datapack for this recipe and didn't write it to all the others in one big datapack.
2. When I uploaded the datapack to my Forge server, the recipe did not work.

The tools I added to the tag always worked.

Have others had problems with it?
In my other datapacks with other mods had always worked perfectly!

I don't know what may be the issue unfortunately, I do not work with datapacks.