That is not what Jesus said. The body was about to ascend after the spirit and soul returned to that same body. You cannot prove all three, body, soul, and spirit were confined to the tomb.
I am not convinced that the body, soul, and spirit can exist apart, despite your belief. I agree that Jesus entrusted his spirit to the Father while he hung on the cross. However, we don't know how the Father kept his spirit unharmed and pure. We know that when the women entered the tomb, they met angels. Presumably, the angels guarded the spirit of Jesus. I don't know this to be a fact, but this is a logical possibility.
The notion of a spirit or soul existing independently of the body is illogical.
I firmly believe that one's identity must encompass their body, soul, and spirit, as they collectively define who they are. When Jesus informed Mary that he had not yet ascended to the Father, he referred to his entire self.
As far as I can see, in Scripture, only the body was confined to the tomb. The spirit returned to God, ie Paradise. The soul went to Abraham's bosom, and immediately left with those who bodily came out of their graves. One can only guess when the spirit and soul rejoined the body, exactly.
We have no Biblical evidence that Jesus' spirit returned to God. In addition, you are incorrect that Abraham's bosom is the same place as God's Paradise. The two locations are much different. And I am not convinced that Abraham's bosom is a real place.
As per Josephus, the Jewish community believed in a place between heaven and hell that they named Abraham's bosom. The Greeks referred to it as "Hades." Here, the souls of the departed awaited the Day of Judgment. Abraham's bosom was divided into two compartments based on Jewish beliefs - one for the righteous dead, and the other for the unrighteous dead.
I am not aware of the origin of Jewish mythology, but there is no scriptural evidence that supports the existence of a place called Abraham's bosom. Jesus used this myth to emphasize the importance of believing in the law. However, we have no Biblical evidence to support the idea that Jesus believed such a place actually existed.
When Jesus says that he did not ascend to the Father, he means that literally.