I am unable to load remote content privately on all of my Apple devices not just iPhone (e.g., iMac, MacBook Pro, etc). How do I get my email to load privately on all devices?

Looks like you use Mail Privacy Protection

Go to Settings -> Mail -> turn Privacy Protection -> Off.

See this Apple article: If you see 'Unable to load remote content privately' at the top of an email

If you see 'Unable to load remote content privately' at the top of an email - Apple Support

I have this problem too, my mail box is not connecting to Bt mail on any apple device, it just stopped after not syncing for a week, , I now have to go to the Bt app or access my e mails via the internet. I have deleted mail and tried to reinstall but it tells me that it does not recognise IMAP passwords. I’ve even taken my phone into a specialist and he cannot sort this out either, it’s so frustrating !! I’ve tried switching off Protect Mail Activity in settings too, to no avail,can anyone help please ?,.,

but it tells me that it does not recognise IMAP passwords.

See -> Change or update your email password

https://support.microsoft.com/en-us/office/change-or-update-your-email-password-58b62e89-6a9b-467b-8865-d5633fcacc3f