How do I disable access to my Epic Account for a specific product or service, such as a site, game, or app?

Go to epicgames.com and log in to your account.
Click or tap your display name on the top right corner of your screen and select ACCOUNT.
Click the CONNECTIONS tab.
In the Apps tab, browse the list of products and services, and tap or click Revoke Access on each one you want to remove.

Use the Account Connections page to revoke third party access to your Epic Games account

If you are already logged in, you can go directly to https://www.epicgames.com/account/connections#apps to manage access rights.