You are rightish in saying that there is just more than Heaven and Hell. There is also Sheol (also known as Hades or Death) This is the place where the dead go before Christ raises them up to be with Him.
However lets get a description of this place.
Luke 16:19-31
Jesus said, “There was a certain rich man who was splendidly clothed in purple and fine linen and who lived each day in luxury. 20 At his gate lay a poor man named Lazarus who was covered with sores. 21 As Lazarus lay there longing for scraps from the rich man’s table, the dogs would come and lick his open sores.
22 “Finally, the poor man died and was carried by the angels to be with Abraham.[a] The rich man also died and was buried, 23 and his soul went to the place of the dead.** There, in torment, he saw Abraham in the far distance with Lazarus at his side.
24 “The rich man shouted, ‘Father Abraham, have some pity! Send Lazarus over here to dip the tip of his finger in water and cool my tongue. I am in anguish in these flames.’
25 “But Abraham said to him, ‘Son, remember that during your lifetime you had everything you wanted, and Lazarus had nothing. So now he is here being comforted, and you are in anguish. 26 And besides, there is a great chasm separating us. No one can cross over to you from here, and no one can cross over to us from there.’
27 “Then the rich man said, ‘Please, Father Abraham, at least send him to my father’s home. 28 For I have five brothers, and I want him to warn them so they don’t end up in this place of torment.’
29 “But Abraham said, ‘Moses and the prophets have warned them. Your brothers can read what they wrote.’
30 “The rich man replied, ‘No, Father Abraham! But if someone is sent to them from the dead, then they will repent of their sins and turn to God.’
31 “But Abraham said, ‘If they won’t listen to Moses and the prophets, they won’t listen even if someone rises from the dead.’”
So we see here that the man who trusted in Christ was taken over to the Heavenly side. The one who had not repented was taken over to the Hell side. It is said that he is there to be tormented, not to have his sins purged. This was also done before Christ’s second coming because the rich man wanted his brothers to here the truth. There is never any indication that this man will get out of this place. And he knows that if his brothers repent then they will not have to go there. So again. No purgatory here.
Your verses in 1 Peter 3 say that Christ in the Spirit preached to those in the days of Noah. That was probably done through Noah. They are now in prison. Which will be the same place as the rich man. Which is the Hell side because they never repented.
David also says in Psalm 16:10**
For you will not leave my soul among the dead (Sheol)
or allow your holy one to rot in the grave.
This shows that he will go to Sheol. However he will go to the side with Abraham where there is no fire.
So yes this is a waiting place outside of Heaven and Hell. But it’s made up of two sides. A Heaven like side and a Hell like side. But it is not Purgatory.
This passage is not talking about purgatory, therefore, does not prove or disprove purgatory. Jesus is only showing us that there is Hell and Heaven. Jesus shows us here how works of charity is important to Him. riches and greed may lead you into hell. taking care of the poor is one of Jesus message.
