Hello,
What I understand is you want to manage it globally and not on the Outlook for every people.
You can check the following : https://learn.microsoft.com/fr-fr/microsoft-365/security/office-365-security/create-safe-sender-lists-in-office-365?view=o365-worldwide - you will be able to manage your safe senders list directly in the admin portal of Exchange Online. You will be able to define some : blocked sender, blocked domain, allowed sender, allowed sender, etc.
Please keep in mind, assistance on this forum is provided in English.
Approve this answer if it's OK for you.
Kind regards, thgibard.