That timeline was exactly my experience with Apple here - https://www.grepular.com/Apples_Protect_Mail_Activity_Doesnt...
They don't seem to know or care what is going on with their own email systems.
Fetching any email content is always worse than blocking it, because the typical threshold for spam is "is this inbox monitored". If that is true, then blast it with spam. And fetching anything ever proves that the inbox is monitored.
I’m still mildly annoyed every email I send using Mail has my IP embedded in it
Has anyone seen Protect Mail Activity get re-enabled after you've disabled it? I wrote about that a few days ago: https://lapcatsoftware.com/articles/2026/6/6.html