since I felt like the tools lack the "diamond part" of the tool, I felt like I could provide a suggestion recipe for the tools I suggested

pickaxe:

Base item: a copper-amethyst combined pickaxe

smithing table reaction:

axe:
base item: gold axe

smithing table reaction:

shovel:
base item: a tainted cobblestone shovel (obtained by just mining off some tainted cobblestone form the fake death of witherstorm)

smithing table reaction:

hoe:
base item: a hoe forged with blaze rods and copper

smithing table reaction:

thats all I have to suggest for now.

I don't feel the recipes of the tools should be changed however this could totally be a cool datapack in conjunction with your resprites.