I’m so sorry for what you are going through.
I’m guessing, maybe wrongly, that as your daughter did not have a diagnosis, they can not accurately genetically test you and your partner? Correct?
I think you have to turn the stats around. So you have a 3 in 4 chance of a healthy child, or a 999,999 in 1,000,000 of a healthy child or a 9 in 10 chance of a healthy child.
I think when you look at them this way, they are way more positive. Ultimately only you and your dp can decide, and know how you will cope if your next child also has the same condition.
However, I have worked with many children who have genetic conditions, and I honestly have not met any, who’s siblings have come along later and had the same condition, even for those with 50:50 chance, or higher.
Now that’s obviously not to say yours will not. But a 9:10 chance of a healthy child, is pretty good going I would say. The reality is no parent is guaranteed a healthy child unfortunately, and you’ve experienced the harsh side of that. But honestly if I was in your position, and my relationship was strong enough that if the worst happened, we were there for each other, I would 100% try for another child. We’ve recently had a baby girl born into our family, and unfortunately her sibling passed away last year. But the joy she has brought ☺️, obviously she’ll never replace her sibling, but there are smiles that we never thought we’d see again on her mum and dad. She has brought so much joy. X