Gloeiwurmpie surgeries and the traumas associated with them are no joke, and your emotions and concerns are 100% valid!
I'm really sorry to hear that you're going through this all again, I would not wish it on my worst enemy!
For me, all I wish is that we could get to her next screening and have good news, and no speak of a need for surgeries, but having been there 3 times in 2 years, and looking like a 4th next year according to Dr's, you kind of start to expect the worst, which is also no way to live.
Try and remind yourself that she is in excellent hands, and that the specialists in SA are really good.
As for contemplating #2, well I just had my 2nd baby last week

It's really 'odd' to have a healthy baby, and I kind of keep waiting to see if something is wrong. But we can't live there.
Kaylee is adapting extremely well to her sister, and likewise, these little kids, as fragile as they are, adapt extremely well to what life throws them. It's usually the parents who take it far worse than the kids. So try and bare this in mind as you try and prepare yourself for this.
And lets rather pray for some good news rather than live in the negative - as it will easily send you into a dark state of depression - trust me.
Big hugs.