Excess deaths is an interesting one, and again can show correlation, but it still can't distinguish cause. Obviously the death numbers were much higher those years, but two major factors were different - the virus was spreading and society responded to it in drastic ways. We can't say how many people died due to lack of access to care for example, or how fear and loneliness factored into death rates.

Excess death rates, at least in the US, are particularly interesting because they didn't follow the pattern I would have expected. Pandemics will effectively pull forward deaths, that didn't seem to happen here. Our all cause mortality spiked noticeably during the pandemic but it came back down to a more normal rate, I would have expected it to be below normal for at least a year or two. Its not as simple as pointing to all cause or excess deaths and saying it must have been vaccine hesitancy - we can't distinguish why those people died and it wouldn't explain the mortality rate after the pandemic.