Importance of 'supported account type' when registering an app with application permission

I build a web app which send mails (with Microsoft Graph) but not on behalf of users. Rather think of a 'do-not-reply email' sent to users with some info. The application should have "Mail.Send" application permission on Microsoft Graph. The mail address is do-not-reply@contoso.com and this is an application mailbox (shared mailbox).

So the basic scenario is:

• User John Doe fill in a form on contoso.com website and submit it
• A mail is sent to the user to confirm the submission of the form
• The mail sender is ALWAYS do-not-reply@contoso.com and the mail receiver is (in this case) john.doe@anything.com

Given my explanations, I think of registering an application on my Azure Active Directory with "application permission" (request for admin consent) Client Crediential Flow. Correct ?

Also, is there any importance when choosing the Supported account types when registering a new application with "application permission" ? From my understanding, since the administrator consent permission from the start of the implementation, this account type choice has no impact.

Please correct me if I'm wrong.