Can accounts that accept calendar invites become mailboxes

Question

We have email accounts that currently are used to accept event invitations, and we're looking to move them to shared mailboxes instead. However, we are unable to get the shared mailbox to automatically accept the request. We have tried other solutions on this forum (such as the one here https://learn.microsoft.com/en-us/answers/questions/1165046/how-do-i-get-a-shared-mailbox-to-auto-accept-invit), but it hasn't worked for us so we're reposting.

Is automatically accepting invitations still available for shared mailboxes? We've tried both methods of using OWA to enable this feature as well as within the Outlook application trying to add the shared mailbox but still with no success. We've also tested on a Microsoft 365 group but there seem to be no settings within the admin center to enable auto invites for calendar events.