If you have a paid Megascans subscription and would like to switch over to the Unreal Unlimited plan, you may do so. If you have an Unreal Engine license, you'll see an option to switch to the Unreal Unlimited plan upon logging in.
You can also manually subscribe to Unreal Unlimited for free by heading over to quixel.com/pricing, scrolling down and clicking on the Get Started button.
Please note that switching to Unreal Unlimited will revoke all your previously accumulated points via your paid subscription. If you wish to keep 2 separate accounts, we recommend creating a brand new account for your Unreal Unlimited subscription.