I have a Survey123 form built on top of an existing feature layer in ArcGIS Online. We exclusively use Inbox to pre-populate a list of site for the user to choose, essentially adding routine repeat visits to the same sites. To share the survey, I created a group in AGOL with the members of our organization that need to use the survey, and then shared the feature layer and published Survey123 form with that group. The editing settings of the feature layer is set to "Add and update features" so the users can submit new surveys for any of the existing sites and fix any mistakes they made on past surveys from their Sent box.
By sharing the feature layer, I realized that these users could then sign in to their AGOL account, open the feature layer from My Groups, and then edit any data that is in the feature layer tables. Here, they could accidentally change the metadata of the pre-existing site we have setup. Editing directly in the feature layer also circumvents all of the constraints and safety checks we have coded into the Survey123 form.
Is there any way to prevent users from editing the feature layer through AGOL or even "hide" shared feature layers from their AGOL account completely? I understand it's probably a catch-22, because I need to share the feature layer so they can add data to it from Survey123, but I also want to restrict access to that same feature layer if they happen to open it up through AGOL.
I understand that publishing the survey publicly would allow users to use the app without a login, which conveniently means they have no login to AGOL, but making these surveys public is not an option.
Thanks in advance for any suggestions!