I'm not really interested in answering a whole lot of invasive personal questions. That has a history of going bad places on the internet and just not going there seems to be the only cure for that issue.
Cystic Fibrosis is much more common in Caucasians than in other ethnicities and there are papers out there that posit that this may be because it may protect against cholera and/or tuberculosis, two diseases that ravaged Europe for some time. So it's possible that the mutation became much more common in White Europeans because of it playing a protective role against those diseases.
Tuberculosis is basically a lung disease while cholera is basically an intestinal infection.
The mechanism behind CF is fairly well understood in that we know it boils down to a miscoded CFTR, which is a channel that handles trafficking of certain molecules into and out of the cell. This impacts all cells in the human body, but especially epithelial tissues and especially impacts the mucosa.
Both lungs and gut tissues are epithelial tissues and both are lined with mucus, so CF leads to serious gut and respiratory problems (among other things). The lung issues get the most press, but about 90 percent or 95 percent of people with CF are seriously underweight due to gut issues interfering with their ability to get adequate nourishment.
So people with CF react differently to most lung and gut infections than the average person and in most cases this is very much to their detriment, but not always. There is some evidence that there are cases where the difference serves as a protective factor and that fact is likely why the mutation is more common in some populations than others.
It would be really, really interesting and potentially valuable if someone took that seriously for wondering exactly how Covid-19 works and why it kills some people while others are asymptomatic while infected.