What about Apple iCloud Mail?

Apple iCloud Mail is less transparent about filtering:

Traditional filtering: Standard content and reputation checks. Less engagement-weighted than Gmail.

Authentication: SPF, DKIM, DMARC are checked.

Limited visibility: Apple provides no postmaster tools. Less data available about their algorithms.

Smaller share: iCloud represents a smaller portion of most sender lists compared to Gmail or Outlook.

Basic deliverability hygiene practices work. Specific optimization is difficult without visibility into their systems.

A harbor that keeps its inspection criteria private. Follow standard protocols and hope for fair treatment.