Confidence intervals for series of Covid tests

All other things being equal …

If I take two antigen tests, both with an individual specificity of 75.3% (95% confidence interval from 65.8% to 83.4%) e.g. from https://pubmed.ncbi.nlm.nih.gov/33455451/

A. what is the sensitivity of the two tests together?

Taking the equation off of https://radiopaedia.org/articles/sensitivity-and-specificity-of-multiple-tests Combined sensitivity: (A)sen + [1 - (A)sen] x (B)sen

That would be 93.9%.

B. But what would I do with the confidence interval? Is it the same calculation?

That would give me 88.3 to 97.2%… Is that the way to do it?

C. So, if I test negative both times, would it be right to say that I am 95% confident that the result is at least 88.3% sensitive? Feels like word salad, but I am trying to get a layman’s grasp here.

Thanks for any help