Hello-
Is it possible to grant/create a user that has content editing access only to one page, having everything else hidden?
Thank you!
Yes, if you put all the resources on the site in a manager resource group (use DocManager) and link that resource group to the administrators user group, that will make the pages protected. Only administrators will see any pages (don’t make the person in question an administrator).
Then put the single page in its own manager resource group and the user in their own manager user group. Link those two groups and the use will have access to the page.