I just read one article that said there is a big delay in death reporting. I'm not sure I understood it correctly
I think it's because of the length of time people are ill. The vast majority of people who catch Covid-19 get ill a few days after being infected, and are ill for about a week. Then totally recover.
The very tiny percentage who are hospitalised do the feeling sick at home for a week thing, then go to hospital, another while in there while they try to treat the pneumonia, then into ICU, ventilator etc if it gets that far. Most don't. So there's a considerable time lag. Plus as well many of the people who have died have underlying health issues and it's a case of disentangling what actually they died of.
It's really not straightforward.