How to reduce the checkout steps for wix online programs?

We are using wix online programs to sell digital courses but it requires the users to register first before they can buy the course, we want to use a custom checkout to sell the courses and then assign the course automatically to the user from the backend. Please guide me if there are any alternatives to it or how we can customize the wix online programs. Note: Our courses are basically recorded videos with limited-time access (90 days).