Is that what Joan of Arc was doing?

That is metaphysical and pagan and not everything in the Bible is a metaphor,allegory or symbol. If Mary was the ark of the new covenant, God would have said so, just as he did concerning the physical ark of the OT. If the new covenant had an ark of the covenant, scripture would have identified it, not left that up to a Pope.
Acts 7:48
Howbeit the most High dwelleth
not in temples
made with hands; as saith the prophet,
the mercy seat of the ark is dwelling place of God
Jesus is God who dwelt in Mary nine months His temple not made with hands
the Holy Spirit overshadowed the Ark
the Holy Spirit overshadowed Mary Lk 1:35 fulfilling the prophecy of Jeremias
2 maccabees 2:1-8
1 Now it is found in the descriptions of Jeremias the prophet, that he commanded them that went into captivity, to take the fire, as it hath been signified, and how he gave charge to them that were carried away into captivity.
2 And how he gave them the law that they should not forget the commandments of the Lord, and that they should not err in their minds, seeing the idols of gold, and silver, and the ornaments of them.
3 And with other such like speeches, he exhorted them that they would not remove the law from their heart.
4 It was also contained in the same writing, how the prophet, being warned by God, commanded that the tabernacle and the ark should accompany him, till he came forth to the mountain where Moses went up, and saw the inheritance of God.
5 And when Jeremias came thither he found a hollow cave: and he carried in thither the tabernacle, and the ark, and the altar of incense, and so stopped the door.
6 Then some of them that followed him, came up to mark the place: but they could not find it.
7 And when Jeremias perceived it, he blamed them, saying: The place shall be unknown, till God gather together the congregation of the people, and receive them to mercy.
8 And then the Lord will shew these things, and the majesty of the Lord shall appear, and there shall be a cloud as it was also shewed to Moses, and he shewed it when Solomon prayed that the place might be sanctified to the great God.
the high priest (heb 8:1) sprinkles the blood of the Lamb (Jn 1:29) upon the mercy seat (Jn 19:25) completing the propitiatory sacrifice ( 1Jn 2:2) fulfilling the redemption of the world!
thks