If the activation fails inside the launcher, try redeeming the code via the website instead.
This error is particularly confusing because it uses the word “Exclusive” — but it doesn’t mean the game is exclusive to another store. Instead, it’s a sign that Epic Games Launcher is having trouble verifying your ownership or entitlement to the game. epic games product activation failed e100 exclusive
Completely close the Epic Games Launcher (ensure it's not hidden in the system tray). If the activation fails inside the launcher, try