Item components don't work

The error message and changelog should tell you that saturation_modifier was changed to saturation

This is because the "food" component has been slightly altered. The "saturation_modifier" field was modified to "saturation". I'm unsure if this is a typo, but there also appears to be a slash in your command that should not be present. A command like the following should work:

/give @s minecraft:diamond[food={nutrition:1000,saturation:1000,eat_seconds:0.1},minecraft:max_stack_size=99,minecraft:rarity=epic] 99