Wouldn't your iPhone still receive spam SMS text messages with Apple Messages? And isn't Apple Messages commonly exploited by NSO Group (Zero-clicks)? Maybe I'm wrong, but this does not appear to be very fort-like.
1: https://developer.apple.com/documentation/sms_and_call_repor...
This explains some things. Why wouldn't they just add a spam filter. Is there still iCloud email addresses? Do they have spam filtering?