To ensure all the items from your different platforms are synchronized with your Epic Games account, follow these guidelines:
- Link all your desired platforms to your Epic Games account
- Launch the game on every platform
- Make sure you make it to the main menu screen
- This needs to be done on every platform that is linked to your Epic Games account
Each platform you link to your Epic Games Account shares its inventory with your other connected platforms.
There are a few exceptions: Which Rocket League items can be shared across linked accounts?
If you've recently made changes to your linked accounts or unlinked an account, you may have to revert your changes. Refer to How Do I Link My Epic Games Account to a Platform for Rocket League?