Thanks for posting and sharing your situation with us. I would recommend doing the diagnostic lap to most folks. For me, it gave me the answers I'd been searching for, and helped me understand more about the disease. I was scared of surgery and honestly I put off going to a gynecologist for at least a year because I was scared they would recommend surgery. Recovery has been challenging for me each time (I've had four surgeries now) but I know for certain it was worth it for me. I have stage 4 disease and had I not ever done surgery it would have led to organ involvement and possibly damage. Before my last surgery I had lost a significant amount of my mobility, and I've got it all back now.
I will say that I was not someone who wanted children, so I was not concerned about the risks to my fertility. I had recurring endometriomas, so I did end up losing both ovaries. Is that the kind of risk you're talking about? I can understand how that would be concerning. I highly recommend you find a specialist who can perform high-level surgery, if needed. I have had four different surgeons and each one was more specialized than the person before them. This made a big difference to my outcomes; I believe if I'd seen my third and fourth surgeon at the beginning, I may have only needed one or two surgeries.
I'm not sure if you know, but excision surgery is the gold standard of care...if your doctor is recommending ablation, I would be cautious about that. It does not fully remove the disease. You can read more about the difference here: https://endometriosis.net/clinical/excision-ablation
If you have more specific questions about the risks, please feel free to reach out here or send me a DM. ~Katrina, Endometriosis.net Advocate