“Porta Caeli” or “Porta Coeli,” meaning “Gate of Heaven,” is an extremely common and ancient title for the Virgin Mary, as well as a common name for Catholic parishes! I guarantee you that St. Alphonsus didn’t think it up!
The reference is from Ezekiel.
Ezekiel 43:1-5
“And he brought me to the gate that looked towards the east. And behold, the glory of the God of Israel came in by the way of the east. And his voice was like the noise of many waters, and the earth shone with his majesty. … And the majesty of the Lord went into the temple by the way of the gate that looked to the east… and behold, the house was filled with the glory of the Lord.”
Ezekiel 44:1-
"And he brought me back to the way of the gate of the outward sanctuary, which looked towards the east: and it was shut.
“And the Lord said to me, “This gate shall be shut, it shall not be opened, and no man shall pass through it: because the Lord the God of Israel has entered in by it, and it shall be shut to the prince. The prince himself shall sit at it to eat bread before the Lord; he shall enter by way of the porch of the gate, and shall go out the same way.””
Mary is the closed Gate of the Temple, just as she is the “sealed fountain” and “garden shut up” of the Song of Songs.
But then we get to the Book of Revelation, which talks a lot about the stuff from Ezekiel. So it’s not surprising that we also find out what happened with the Closed Gate:
Revelation 11:19 - 12:1 –
“And the Temple of God was opened in Heaven: and the Ark of His Covenant was seen in His Temple, and there were lightnings, and voices, and an earthquake, and great hail. And a great sign appeared in Heaven - a woman clothed with the sun, and the moon under her feet, and on her head a crown of twelve stars…”
But yes, literally we do come to Heaven by way of Jesus, and God willed that Jesus would be born into the world as the son of a woman, Mary. Just as we wouldn’t get to Heaven except for the existence of Abraham and Sarah, and David, and Solomon, and even of many great sinners, God brings us to Heaven by Jesus, through Mary. If you don’t like salvation history, it’s a bit late to disapprove of the way God likes to do things.