Hmm...actually Let's just say she has Checkpoints off this time so her Regen would only be Mid.
Also to give some of Apeiros' abilities, well...she also has the intelligence of everyone she's absorbed including all of their martial arts and whatnot which is several thousands of some of the strongest warriors in the galaxy so I'll get that out there. But in essence she has at the very least absolutely mastered and perfected every single fighting style on earth, and knows how to counter...practically all of them.
Surprisingly, in story, Apeiros was able to still fight for quite a while. I might be selling her Stamina a little short actually and never really specified but she could fight with a character who's stamina was nigh limitless Who isn't complete but I hope that gives perspective.
She's also dealt with very, very smart foes before, like the very scientist who created her and, ironically, a girl with Sun and absolute hot fire powers. Her cockiness would likely make this battle even more drawn out however at this point in the story, she is much more careful when dealing with opponents so it won't hinder her quite as much this time.
Her magical supply is also gigantic at this point in time so that won't be too much of an issue for her either.
She also has evolving defenses that make it so Apeiros is capable of getting passed nearly any ability an opponent has as long as she is able to absorb them at some point. It does take quite a while but considering fights she had previously with people who could alter fate, time, probability, alternate quantum realities, her existence in it's entirety, etcetera, it would be able to do so. Even being described as being sort of sentient in a way.
I mention her Boundaries she could manipulate are extremely nerfed in her universe, however, Apeiros was still able to manipulate probability just enough for her attacks to hit more often and whatnot...even against an opponent who had instinctive reaction to the point that she could otherwise be able to block every one of her projectiles instead having multiple projectiles able to hit her.
In the end, killing SOL will be...not an easy one to say the least, so I'm not sure on this.
