This will hide the Gear and Crafting buttons in the inventory so your player can no longer craft items without interacting with a crafting bench, if you want to totally disable crafting just follow this guide and do not include any crafting benches in your game levels.
Start by going to the BP_InventoryHUD and copy the video below.
The player will now no longer be able to select the crafting menu without interacting with a crafting bench.
Optional: You can increase the size of the gear panel to match the other panels by following the video below.
If you want to change the layout of the gear panel to better fit the new size just head over to the BP_CharacterEquipment widget and make the changes in the designer there, remember to see the changes in the BP_InventoryHUD you need to compile the BP_CharacterEquipment.