Personally I think making decisions based on attempting to avoid regret isn't the best way, as regret is internal and part of life. Regret is a natural emotion that tends to rear its head whenever we are in a tough position - it's part of the grief and bargaining and wanting to feel in control again by blaming ourselves for our difficulties.
We all regret different things for different reasons, I'm not sure how helpful it would be to you to know my regrets.
A better way might be to weigh up which set of risks you are most comfortable accepting, and which "worst case scenario" for each option you are the least uncomfortable with.
It sounds like you are more comfortable with the risks of CS, but are worried about the enormity of the decision and how to manage your feelings afterwards?
It is normal to feel scared and apprehensive about this decision. It is normal to feel scared about surgery if that is the path you take. It doesn't mean it's not the right decision, just that it's a big deal and you're human!
It is major surgery, but people have major surgery every day. It's not in the same category as transplant surgery or other major procedures where you always require an intensive care bed immediately afterwards (whereas for CS that would only be the case if complications arise), to put it in perspective.
Major surgery isn't fun, but it's not insurmountable either. It can be a shock not to be able to use your core muscles for a while, and that can be emotionally challenging, but as you recover it can also make you appreciate what your body is capable of and how strong you are.
Anyway, that's my opinion based on having made some rubbish decisions in the past based on trying to avoid regret! I don't make decisions like that anymore and I think I get better outcomes now, even if sometimes they're still tough because sometimes life is tough whatever you do.
I wish you all the best whatever decision you make.