I would leave God out of this for now and focus on what kind of things you accept as moral standards and what you don't. That narrows it down to what it's possible for you to forgive in your lifetime or not.
I have the chance of making peace with one of my abusers right now, and it's been incredibly difficult to separate the person from the behaviors. This particular perp acts out of mental health issues, not true evilness. Another one of my abusers for example, I can't separate the person from the behavior. I think he is evil, and I have periods of compassion for the shit he endured in his life, but I haven't forgaven him. That speaks about me, not him at all. He's no longer in my life, why should he have that much of a hold of my emotions?
"What others think of me is none of my business" applies to what we think of others as well.
One of my own goals for myself is to separate myself from my traits. I mean, I have a stubborn trait, but I am not a stubborn person. But when I think harder about it, and try to apply it to others, it's really hard to see any other person separate from their traits.
Like, I have a neighbour who went through trauma as a child, we discussed a bit about it. She never really got over it, mostly because she had huge damage in her mind due to it and there's a constant reminder. I am getting over it, baby steps, but I don't have a constant reminder in myself of it. Do I say she is her trauma? No, but as my trauma belongs to me, so does her's belongs to her. What she does with it matters to her, not to me. What I do with mine, matters to me but not to her. At the same time, we share and talk and that is fine. We share compassion towards each other.
Same with perps. What happens to them, belongs to them. And they were the ones who refused to share our compassion, not us. So, we may have compassion towards what they've been through but not be compassionate towards the evil they do.
And I don't think we need to compare our own evil with it to relate to them and forgive them or whatever. We don't have the same evil, we don't do the same things. What we share is a story, we were in that story, and our minds constantly tell us that story, but it's nothing more than that right now.
Looking at people in general walking on the street, you can't really say which ones of them are victims of abuse, or are abusers.
If you want to think some guy is camped on the moon looking down seeing dots walking around, that guy has no idea which dot is what either. So, trying to be in that observer perspective, you can really connect to the idea that people are as superficial as they are complex, and they can actually be both abusers and victims of abuse.
What we do with our stories matters, sure, and if you believe in eternal damnation you've got your life made easier for you.
I really don't, so I've got to live with the idea that they will live merry lives even having done what they did. So it's up to me if I want to forgive them or not, but they will never really know, because it's not for them or their story - which is completely separate from mine at this point - it's for me and what I intend to write in my story. Right now they're just a dot that the moon guy sees just as equal as he sees me.