Spam Filters

Outlook is a client, not an email platform, so it has limited anti-spam features (read Microsoft no longer invests in them, in favor of the Defender suite). You would usually configure such filters on the hygiene product you are using, and should not rely on Outlook.

That said, the built-in Junk Email Options do still support blocking top-level domains and countries. Other top-level domains can simply be added under the list of blocked senders.

Here's an example article with instructions: https://support.microsoft.com/en-us/office/use-junk-email-filters-to-control-which-messages-you-see-274ae301-5db2-4aad-be21-25413cede077