The context of Revelation 6:9-11 shows that the illustration is figurative. The four horsemen are figurative. Death and the Grave are figurative. The altar and souls scene is figurative. It's not literal.
First Corinthians 15 in context is talking about Christ's resurrection initially. Then Paul is explaining how the heavenly resurrection works.
Why did Paul focus on Christ's resurrection and not mention all the earlier resurrections recorded in the scriptures? Because Christ's resurrection was different. None of the other resurrections, either the ones by Elijah or Elisha or even by Jesus himself during his ministry on earth, were of a "new creation". Those other resurrections were of people back to life again in a human body. When Christ was resurrected, he was raised up by God in a spirit body. He materialized a human form in order to interact with his disciples, but he was not human anymore.
Paul was explaining this to the Christians in Corinth because they had the same eventuality to be a new creation. People prior to Jesus' resurrection did not have that same eventuality. The Bible shows humans are meant to live on the earth. There is no need to live in heaven, because Jehovah and Jesus are going to come here anyway. (Jesus' abode is heaven but he can come here whenever he wants, so can Jehovah.) The whole provision of 144,000 priests and kings to help restore things is a temporary arrangement just like the ancient priesthood was temporary. The "new creation" and "marriage of the Lamb" part will last, it is a way Jehovah can show the Devil and the demons and the faithful angels and humans that humans are not unloved or some lowly junk to throw away. (The Devil made all kinds of accusations in heaven. By taking some of the lowliest of the lowly humans and making them higher than angels, Jehovah shows that He is not partial, and that the youngest in His family are just as loved as the oldest.)
This guarantee and great love of God for all His faithful kids is to be expressed to all humans who want to embrace it, the sacred secret that God will be here on earth with all His kids. It's not necessary to be one of the 144,000 new creation in order to hang out with Jehovah and Jesus.
When Paul was talking about the "third heaven" that's what he meant. Peter helps explain it when he said that in Noah's day "the heavens were destroyed" (the first heavens) meaning the governments of that time. Peter said that soon again "the heavens will be destroyed by fire" (the second heavens) figuratively, when the governments are replaced by God's Kingdom government (which is the third heaven). (2 Peter 3:5-7) Sometimes the word "heaven" can be used figuratively to describe government. It's the Kingdom government that will help make the earth a paradise. Paul said he had a vision where he was "...caught away to the third heaven...caught away into paradise and heard words that cannot be spoken and that are not lawful for a man to say." (2 Corinthians 12:2-4) He was talking about the sacred secret. It wasn't the time to talk about it then, but now it is.
The sacred secret is that everybody who wants to can hang out with God. You don't have to have "the heavenly hope". He's coming here.
That's why it will be Paradise. Because God will be here.
"And I saw a new heaven and a new earth; for the former heaven and the former earth had passed away, and the sea is no more. I also saw the holy city, New Jerusalem, coming down out of heaven from God and prepared as a bride adorned for her husband. With that I heard a loud voice from the throne say: “Look! The tent of God is with mankind, and he will reside with them, and they will be his people. And God himself will be with them. And he will wipe out every tear from their eyes, and death will be no more, neither will mourning nor outcry nor pain be anymore. The former things have passed away.” And the One seated on the throne said: “Look! I am making all things new.” Also he says: “Write, for these words are faithful and true.”"
Jesus is the faithful witness. He said "Truly I tell you today, you will be with me in Paradise."