Admins can through sharing settings, group permissions, conditional policy and so on to secure SharePoint.
And please refer this article for Forms and this article for Power Automate.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.