How can I publish my game as vaultcache resource?

How can I publish my game as vaultcache resource?

You can’t, at least not in the way you think.

Once you save your project it shows up in your vault cache (in the launcher, not in the vault cache folder unless you saved it in that folder)

For it to be an actual vault cache folder you either have to be Epic Games, or you need to publish your project on the marketplace.

You can submit your content to the marketplace by following this link:

https://publish.unrealengine.com/seller-information