Mail app - Send later sync between multi devices

If I schedule an email to send later on my Macbook the email jump onto the folder "Send Later." Nex, if I open my mail app on the iPhone, the emails that I scheduled on my Macbook don't show up on my iPhone. This issue happens the same if I schedule an email on my iPhone and next open the mail app on my Mackbook, the email scheduled doesn't show up as well.

This is frustrating because I often schedule an email on my Macbook, and I need to reschedule the send from my iPhone, but it's not possible because that email created from my Mackbook is not available on the folder "Send Later" on my iPhone. As I said above, the same happens between iPhone to Mackbook as well.

To be clear: The hand-off feature is active on my Macbook, and the iCloud Mail sync is active for both devices.

Anyone can help me with this? Apple hasn't supported this feature yet? I've been struggling with this issue and haven't seen any topic about it yet.