Please help, 343! Custom map transfer

(This is my second time posting this) I have 60+ Halo 4 custom maps on the original game I have been trying to transfer to MCC on Xbox one. The frustrating thing is apparently there was a one time shared files transfer quite a bit ago that I didn’t know about. A few of my old maps made it onto MCC that were already in file share from my 360, so I know it should be possible. Is there anything I can do here ? I’ve just spent too much time over the years making all these maps to give up on the transfer.

Please keep to your existing topic, thanks
https://www.halowaypoint.com/en-us/forums/85d779d52cfd46918b4f8b638f2e3c7b/topics/halo-4-custom-map-transfer-to-xbox-one-mcc/b6c4dadc-9c86-4dc8-8c5a-071403109100/posts?page=1