"To learn more about how to create safe overrides, see https://docs.microsoft.com/en-us/exchange/troubleshoot/antispam-and-protection/cautions-against-bypassing-spam-filters"
That page doesn't really have any useful information or instructions for creating safe overrides.
This page talks about creating "safe senders", which I believe is achieving the same outcome
https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/create-safe-sender-lists-in-office-365?view=o365-worldwide
The instructions there seem to counter your other advice, i.e the number two best way to make a safe sender is via: transport rules, but you call this a legacy method in this article.
Can you clarify the preferred way to allow known senders through?and which options are recommended?