How do we explain infinity to atheists?

How do we explain infinity?

Why does everyone get infinity wrong?

I could start at 0. I could say there is a set of positive integers from 1 to Infinity. That set would be infinite. It would not include (non whole) fractions. It would not include (non double) negatives. It is still infinite.

God is all powerful. That means God can do all things that are doable. That is the set. If something can't be done, it isn't in that set. It doesn't in any whey diminish God's power that we can come up with goofy stuff like "a rock so big God can't move it." That rock doesn't exist. It can't be made because it isn't in the set of things that can be done.

God is all knowing. That means God can know all things that can be known. We don't know what can be known and can't. We can't define that set. Doesn't mean God doesn't know absolutely everything that is knowable.

Infinite sets are undefined, by rule.

The undefined exists. Even those who hold a secular world view believe in either an infinite universe or a singularity at the beginning. There is some undefined characteristic to every world view. What don't atheists understand about that?

Choice is something we haven't been able to define as humans. We aren't sure and some think the universe is deterministic. Well, the Bible says we have choice. Just bc we can't understand that and would rather conclude the universe is deterministic... thay doesn't make it so. It's something undefined to us.

A dog will tend to choose to eat food it can access. Even if it is trained to wait and not eat until a signal is given that gives permission, we still don't force the dog to eat. The dog could choose to not eat. We train it to abstain. We could take the food away before giving permission and it would not eat that food, assuming it followed its training. But when the food is accessible and permission is given... the dog chooses to eat. We don't force the dog simply by providing food and giving permission. I think we see this is true when animals bring food to us as if we were in the pack. That all said: I can feed a dog.

Maybe that's a small picture of God's infinite knowledge and our choice. God can plan to save us without taking away our choice. God's plans don't fail. He is soverign. He predestines and it comes to be. That's undefined to us but it still exists. It still doesn't counter logic.

Tldr question: why do atheists often get Infinity/undefined concepts wrong and assume it makes Christianity false? Their view has it too.