I would describe them more as prophecies rather than parables, right?
No, the Isaiah 54:1 example is a parable, because it is using an analogy to tell a story, and you have to understand the analogy in order to understand what is literal about it.
In Isaiah 54:1, we are told that the barren woman will have more children than the married wife. Barren means a womb that doesn't bare children.
1. We first have to understand the analogy about woman's womb given in the parable.
2. The woman whose womb is barren (without child) is to have more children than the married wife. This doesn't make sense if we try to understand it literally. Reason is because a barren woman doesn't have any children.
3. The married wife has less children than the barren woman. Again, this doesn't make sense literally, because the married wife having children is a natural state God created, and nothing bad about it, which is why we know God is giving a parable here, comparing things in analogy. So there's a Message kind of hidden within this.
4. Continuing into the next verses shows how the barren woman will have more children than the married wife, and the analogy then takes on a faithfulness Message. The barren woman (without child) suffered for a time, but eventually is relieved of her barren state, and the comparison is given in conjunction with Israel having to enlarge the symbolic tent to include believing Gentiles, pointing to Christ's Salvation in the future in the land, i.e., after His return.
So when we get to the New Testament passages like this, we know this is one of the places where our Lord Jesus and His Apostles were referencing about staying faithful... waiting on Jesus' return:
2 Cor 11:2-4
2 For I am jealous over you with godly jealousy: for I have espoused you to one husband, that I may present you as a chaste virgin to Christ.
3 But I fear, lest by any means, as the serpent beguiled Eve through his subtilty, so your minds should be corrupted from the simplicity that is in Christ.
4 For if he that cometh preacheth another Jesus, whom we have not preached, or if ye receive another spirit, which ye have not received, or another gospel, which ye have not accepted, ye might well bear with him.
KJV
Paul there was warning about the "another Jesus" that some would preach, which was about Christ's warning in His Olivet discourse regarding the pseudo-Christ of Matthew 24:23-26 that is to come. We are to stay a symbolic 'chaste virgin' waiting on the True Jesus to return, and not fall away to the fake one that comes first.
Luke 21:22-23
22 For these be the days of vengeance, that all things which are written may be fulfilled.
23 But woe unto them that are with child, and to them that give suck, in those days! for there shall be great distress in the land, and wrath upon this people.
KJV
The "days of vengeance" is about the end of this world when Jesus returns. It was foretold in Isaiah 61...
Isa 61:1-2
61:1 The Spirit of the Lord GOD is upon me; because the LORD hath anointed me to preach good tidings unto the meek; he hath sent me to bind up the brokenhearted, to proclaim liberty to the captives, and the opening of the prison to them that are bound;
2 To proclaim the acceptable year of the LORD, and the day of vengeance of our God; to comfort all that mourn;
KJV
Everything in blue was about Christ's 1st coming to die on the cross. That He read from the Book of Isaiah to begin His Ministry per Luke 4. When He got to the part in green, He closed the Book. That part in green is the time of His future 2nd coming. This is something men's doctrines want to hide when they miss-teach Luke 21. Even that latter phrase in the Luke 21:22 verse about all things written being fulfilled ought to be a huge clue that Jesus was speaking of the end of this world, the day of His 2nd coming.
This idea of being 'with child' is linked to those who suffer that "wrath" there on the day of Christ's coming. What wrath is that?
Rev 16:15-17
15 Behold, I come as a thief. Blessed is he that watcheth, and keepeth his garments, lest he walk naked, and they see his shame.
16 And He gathered them together into a place called in the Hebrew tongue Armageddon.
17 And the seventh angel poured out his vial into the air; and there came a great voice out of the temple of heaven, from the throne, saying, "It is done."
KJV
Jesus is warning His Church still on earth there on the 6th Vial. He is still telling us to 'watch' (i.e., not be deceived by the false messiah). The next event is the battle of Armageddon on the day of His coming, the 7th Vial, and then per Rev.19, His cup of wrath is poured out upon the wicked, which is that 7th Vial.
In Luke 23, Jesus shows this 'with child' analogy de facto. While He is carrying His cross, women in Jerusalem watching Him are crying, and He turns to them and tells them to not weep for Him, but weep for themselves and for their children, because the day will come when those daughters of Jerusalem will say,
"Blessed are the barren, and the wombs that never bare, and the paps which never gave suck." (Luke 23:29).
Those deceived will be saying that after His return, and they will be saying it about the faithful who remained 'chaste virgins' with spiritual wombs that were not 'with child'.
So this idea here in Luke 21:22-23 is not about literal pregnant women fleeing a disaster, it's about spiritual harlots who are deceived and are spiritually with child, already married when Jesus comes, but not to Him, but to the pseudo-Messiah that comes first which our Lord Jesus warned us about (Matthew 24:23-26; Mark 13; 2 Thessalonians 2; Revelation 13:11 forward).
One more example... of the barren vs. married wife parable in Isaiah 54...
Rev 18:7
7 How much she hath glorified herself, and lived deliciously, so much torment and sorrow give her: for she saith in her heart, "I sit a queen, and am no widow, and shall see no sorrow."
KJV
That's about the Babylon harlot of Revelation, for the end of this world. She says she sits as a queen, and is not a widow.
That idea is about Jerusalem. God married Jerusalem per Ezekiel 16, spiritually. So this is about fallen Jerusalem as the Babylon harlot in the last days just before Jesus returns. Jerusalem in the Isaiah 54 parable is considered to be in widowhood until God literally returns for the future Marriage of Revelation. However here... the "great city", the Babylon harlot, instead says she is already married, and is not a widow! So who at that time would she be married to, because Jesus has not returned yet at that point? Who is coming to be her false husband in God's place??? The Antichrist, the dragon, the another beast, the pseudo-Christ, the little horn, the vile person, son of perdition, man of sin, that Wicked, etc., he has many names.
So the Isaiah 54 parable is not applied only to Christ's Faithful whose spiritual wombs remain barren, waiting on His return, but it is also applied to the deceived and even Jerusalem itself, as being already spiritually married to the wrong one.