Outlook won’t open as default mail app

I use Outlook for iOS as my default email app. I do NOT use the Mail app. However, despite me having set Outlook as the default email app whenever I am in another app and wish to send an email via that app it opens Mail instead of Outlook. Unfortunately I have no email addresses assigned that I can use and the mail app won’t allow me to manually enter my usual email address.

One of the apps that does this is the DayOne journaling app.

what can I do to force these apps to open Outlook rather than Mail?

thanks

Martin