Using Exchange email in Mail on iOS and MacOS how can I have a single Junk folder? If I mark an email as junk in Mail on iOS it puts it in a folder called "Junk".

If I mark an email as junk in Mail on MacOS it puts it in a folder called "Junk Email".  This was a little hard to spot at first as Mail displays this folder as "Junk", you have to see it on other devices (e.g. Mail on iOS) or the web app to see that the folder is actually called "Junk Email".

My question is this: how can I tell one of these OSs to use a different Junk mail folder?
On your Mac, in Mail.app, go to Preferences → Accounts → account name → Mailbox Behaviors and set Junk Mailbox to the correct mailbox.