I don’t think Abraham went to Hell. Once in Hell, always in Hell. When I was a child, I always pictured those who died before Christ’s death as being in sort of a holding pen, until God decided what to do with them. Chidlish, huh?
As you quoted:
847 This affirmation is not aimed at those who, through no fault of their own, do not know Christ and his Church:
Those who, through no fault of their own, do not know the Gospel of Christ or his Church, but who nevertheless seek God with a sincere heart, and, moved by grace, try in their actions to do his will as they know it through the dictates of their conscience - those too may achieve eternal salvation.337
If one believes that those not Catholic go to Hell then I would say they are denying what the Church has stated. We cannot make that final judgement. Only God can mke that final judgement and God is all merciful.

Peace
You know this is certainly not the first time people have made these accusations that I’m not following the church. This week as I was arguing this I picked up my bible and opened it at random and I came to the story of St Paul’s imprisonment in Jerusalem in the Acts of the Apostles, what particularly struck out at me in his defence was when he was saying that he was upholding the entirety of the faith of their ancestors that he was being accused of corrupting. I don’t think it was coincidence that I opened to that either.
No, my friend, the tradition is that they did indeed go to hell, or sheol, or the underworld, I have heard it said though that this hell is understood to be a different place than final damnation, which as you say there is no return, what I would point out though is that there does not appear to be differentiation between where the wicked and the righteous go before Jesus:
Psalm 6:4 Turn, O LORD, and deliver me; save me because of your unfailing love. 5 No one remembers you when he is dead. Who praises you from the grave?
In the first verse we see here that where they go when they die they no longer remember God and do not praise him.
Psalm 16:8 I have set the LORD always before me. Because he is at my right hand, I will not be shaken. 9 Therefore my heart is glad and my tongue rejoices; my body also will rest secure, 10 because you will not abandon me to the grave, nor will you let your Holy One see decay
In the second verse I quote we discover the hope that those in the old covenant had that they would not be abandoned to sheol, but would raise up from it.
Psalm 49:10 For all can see that wise men die; the foolish and the senseless alike perish and leave their wealth to others. 11 Their tombs will remain their houses forever, their dwellings for endless generations, though they had named lands after themselves. 12 But man, despite his riches, does not endure; he is like the beasts that perish. 14 Like sheep they are destined for the grave, and death will feed on them. The upright will rule over them in the morning; their forms will decay in the grave, far from their princely mansions. 15 But God will redeem my life from the grave; he will surely take me to himself. Selah
Third verse, the same hope is present, that the life of the righteous person will be redeemed from the grave while the tombs of the ‘foolish and senseless’ ‘will remain their houses forever’. I think this implies that both the righteous and wicked went to the same place prior to Jesus does it not? I say this because there is no differentiation anywhere that I can find, and they even use the same words and wording for describing where they both go, the difference is that one suffers final damnation while the other will be one day redeemed from that place.
Psalm 88:3 For my soul is full of trouble and my life draws near the grave. 4 I am counted among those who go down to the pit; I am like a man without strength. 5 I am set apart with the dead, like the slain who lie in the grave, whom you remember no more, who are cut off from your care. 6 You have put me in the lowest pit, in the darkest depths… 10 Do you show your wonders to the dead? Do those who are dead rise up and praise you? Selah 11 Is your love declared in the grave, your faithfulness in Destruction? 12 Are your wonders known in the place of darkness, or your righteous deeds in the land of oblivion?
Fourth verse, ‘land of oblivion’, ‘place of darkness’, ‘remember no more’, ‘who are cut off from your care’, ‘in the lowest pit, in the darkest depths,’ - in a word, hell
I could keep quoting but I’ll stop.
We cannot go to heaven unless we are freed from sin, and we cannot be freed from sin in any other way than Jesus. Hence, all these righteous men in the old testament, despite their faithfulness nevertheless having inherited original sin and committed sins died in that sin without His grace which had not come to the world. The same is likewise true of all non-christians, no matter how righteous they may be.
I am not in opposition to what the church teaches, because I do think that these people in the words of the catechism may indeed somehow find salvation if given opportunity, but I know for a fact that you need to be christian in order to enter heaven. I don’t know how they will get there, I simply put forward theories that perhaps they go through something like what Abraham went through, or perhaps they will believe at the resurrection and then inherit salvation. I don’t deny that they may indeed find salvation (which is what the catechism says) at same point in the future, but I know that unless they become christian somehow, they cannot inherit eternal life.
How do you suppose that the tradition of the church holds that infants dying without baptism do not inherit salvation? I think that must be considered similarily to people who never encountered the gospel.
And I agree God is the only judge of this and all things are possible with God.
Peace be with you,