Genshin Impact has a large crafting system which allows you to craft:
Most of the items can be used to generate/craft a next-tier version of it. So only a little items are unused
Right now there are 10 weapons, 2 of each type, which are craftable with a prototype.
- Prototype Weapons
- Infusion Weapons
These prototypes can be bought with regional currency (sigils), found at large-scale bosses (Stormterror) or are rewards in the main storyline.