How to recover deleted emails older than 30 days from iCloud on iPhone?

You are correct that deleted iCloud emails only remain on Apple servers for 30 days. That allows recovery during that time while still protecting your privacy by not storing your data any longer and also not filling up your iCloud storage with emails you have already deleted.

Backups don't include emails, it is the email provider that stores your emails and when setting up a new device or resetting a device, the emails stored on their servers are downloaded to your device.

For other mail accounts, such as your work email, you can set how long you would like deleted emails to remain on their servers in the Mail Settings for that account, but the email provider can remove them before that time to comply with their privacy policy.

• Note: Some email services might override your selection; for example, iCloud doesn’t keep deleted messages longer than 30 days, even if you select Never.

Delete and recover emails in Mail on iPhone - Apple Support

Caz_Baz wrote:

I have an iPhone and use icloud. I now understand that iCloud delete all deleted emails after 30 days. Is there no way to get them back after that? I know my work emails are never truly deleted. I have auto back up turned on. I need to find a deleted email from 60 days ago and think there must be a way. My email server is also iCloud.

[Re-Titled by Moderator]

Original Title: Recovering deleted emails

You cannot recover permanently deleted iCloud emails directly from Apple once 30 days have passed or once the Trash has been emptied. Apple permanently erases these messages from its servers, and iCloud Mail does not keep a hidden or server-side archive past that window.

Works email are permanently deleted unless your IT administrator purchase a 3rd party software to retrieve them if you're using Exchange.