Seems that all Covid data is hard to trust. There is a question of test availability and significance. There is an article that a large percentage of elderly in hospitals are Covid positive. How many of them are there because of Covid and how many have Covid (often through hospital exposure!) and are being treated for more serious things. Similarly, the deaths may be overstated where hospitals are reimbursed for COVID deaths and understated where governments don't care about the reporting. It is remarkable we collect so much data and there is a ton of noise in it.
You're right that it is crazy that no reliable studies have really been done. I think this is because at the very beginning there was tension between the containment and mitigation objectives, and the former required that no control group exist. I wouldn't describe the data problems you mention as noise, but rather bias. Bias is arguably easier to correct for.
Seems that all Covid data is hard to trust. There is a question of test availability and significance. There is an article that a large percentage of elderly in hospitals are Covid positive. How many of them are there because of Covid and how many have Covid (often through hospital exposure!) and are being treated for more serious things. Similarly, the deaths may be overstated where hospitals are reimbursed for COVID deaths and understated where governments don't care about the reporting. It is remarkable we collect so much data and there is a ton of noise in it.