If you to play the game with your friends, make sure your friends are using the same platform on which you are playing the game.
For delivering food to Ernest, Sara will give you a lot of things such as Crab, Ham and Veggie.
Here's a quick guide on how to obtain Fading Star Might in Genshin Impact.
Here are all the ingredients that classified as "Liyue Local Specialty":
Here's an updated list of Soul Knight gift codes and free gems.