Hi Christy,
Welcome to the Answers community.
Responses in Excel syncs to online location only when we create the from in OneDrive for business or SharePoint online or Excel for the web.
When we create a group form by going to Microsoft Forms and clicking the site name under My Groups and selecting New Group form (as shown below), it also creates a form that has the Excel responses syncing to associated SharePoint library. It is because the form creation experience is same as the one we create in OneDrive for business or SharePoint online or Excel for the web.
When it comes to quizzes, we can create quiz only in Microsoft forms, we can’t create it directly in OneDrive for business or SharePoint online or Excel for the web, so this is the reason quiz response can’t be synced to OneDrive or SharePoint library.
We understand it is important feature and it would be convenient if quiz response also syncs to online location just like forms and in this regard, we would like to invite you to provide your feedback in Microsoft Forms UserVoice and let the Product group know your requirement. UserVoice is the best way to give the feedback to Product Group as it’s actively monitored by them and many new features have been implemented from our customers feedback.
We appreciate your understanding.
With sincerest regards,
Neha