Can you add the attachments, I do not want the end user to select the attachments.
The docs says (Dated 10/20/2022)
Attachments that you add to an email by using the EmailAttachment class will appear only in the Mail app. If users have any other mail program configured as their default mail program, the compose window will appear without the attachment. This is a known issue.
Reason I want to use Outlook
"Beginning in 2024, new Windows 11 devices will be shipped with the new Outlook for Windows as the default mailbox application"