Unable to Move eMails on Apple Mail (iOS) from an imap account folder to Exchange/ outlook.com account Folder

On the native mail app of ios, can't move emails from any imap account folder to my Exchange / outlook.com mail account, On native mail app of ios. the Exchange/ outlook.com mail account appears greyed out. I have no problem moving emails from the Office 365 Exchange account or outlook.com account to IMAP folders, but I can't do it the other way round.

I also have no problem doing this on macOS – the Mail.app on my two Macs does it straight away, dragging & dropping, and those changes are instantly reflected on my iPhone & iPad. I just can't perform the task of moving an email from an IMAP account over to the Office 365 Exchange account or outlook.com account, because it's not an option – it's greyed out in the list.

Even when Mail.app on iOS suggests a particular Exchange/ outlook.com account folder to move the email to (because I've done the same previously, with related content), it just says "Unable to move email" and it stays in the IMAP Inbox.

So, it works on macOS, but not on iOS.

any solution ?