That covenant includes being under the line King David. You are the one with the struggle.
Read closely, SINCE CHILDREN SHARE IN THE FLESH AND BLOOD, HE (JESUS) partook of the SAME.
Hebrews 2
14Therefore, since the children share in flesh and blood, He Himself likewise also partook of the same, that through death He might render powerless him who had the power of death, that is, the devil,
Hebrews 2
17 For this reason He had to be made
like His brothers in every way, so that He might become a merciful and faithful high priest in service to God, in order to make atonement for the sins of the people.
You are wanting a viable fetus transplanted into Mary. Not happening. It would violate the scriptures. The old testament is clear with the lineage to David.