Actual studies measure these rates. Your limited knowledge of your extended acquaintance group means jack shit for whether they're correct. I only know of a single person in my extended acquaintances who had heart disease. It doesn't mean that general population statistics on heart disease are wrong, it means some combination of I'm missing information and my sample is biased. Your sample is not random (so multiplying a statistic of the general population against them is not valid) and you don't actually know who's experienced long COVID symptoms. Some may have had some and gotten better, some may not even recognize a lingering cough or being more worn out as a symptom, and some may just not feel like it's necessary to tell you.