The article will help you to replace the existing pre-designed success page in journey with the website.
Templates
To create a template with website, Navigate to Configuration>Splash Page>Templates>SuccessPage
Success Page Name: Name of the success page
Select Page Type: Select page type as Success URL
Success Page URL: Enter the success page URL
Click ‘Add Page’
Edit the Redirection URL
To edit the success page redirection, Navigate to Configuration>Splash Page>Journey
Click ‘Edit’
Click ‘Next’
Under Success Page, select the new website redirection template
Click ‘Add Rule’
Click ‘Finish’