As of 1.1.1, all the shields for TechReborn's recipes are dynamically generated. This should also apply to:

• Shield crafting advancements(to make shield's crafting recipe be discovered when an item is picked up)
• All the vanilla material types
• Smelting recipes for Netherite shield and future integration shields

This issue is almost completely done. It's just that dynamically generating advancements seems to be a lot harder than I thought.

This is done for now