Of course, you are or rather you have every reason to be sure.
Why do doctors/coroners try to make us believe that certain deaths are not because of coronavirus?
It has to do with the way doctors think: there are no healthy people, and in fact, everybody is sick (with a developing illness) but undiagnosed. So, when only just a little is required to kill somebody because his/her heart can't stand very much anymore - it may be qualified as a heart attack.
The question is how far can this line be drawn - and what if coronavirus makes the picture blurry - because what if it leaves the heart in such a bad condition that it really looks like many years of abuse.
So this is all simple from the doctors' point of view and nobody will even think twice - maybe with time doctors will start to notice a pattern that the virus leaves the heart in a bad condition and that the virus is the cause of death. But until this is confirmed they assume that only lungs are attacked.
But it gets even worse... ie. this is entirely untrue that these people were killed not by the coronavirus.
Understand this: people with very low heart capacity can live for years. Maybe breathing oxygen all the time but still.
Then they might get better therapy, better drugs, a heart transplant, bypass surgery, and most importantly supplements like carnitine.
Thus they could live for another 10 or 20 years if they are lucky to have good insurance, find a good doctor or search the web to find supplements for themselves. Many older folks do take supplements. But many don't take the most needed ones just "something" as prevention. However, most of them don't even care and don't take anything. At least that's my observation.
So the final conclusion is: if we assume that people get the best possible care (even if their condition is already not that good) then these people might live for the next 10-20 years. Of course, they don't get the best possible care now but if they survived they could live to see the times when the healthcare system is much much better - this is already happening thanks to better tests, drugs, etc. and even smartphones play a role in this improvement.