The only solid metric for COVID-19 deaths is excess mortality, that is, the actual number of deaths - the statistically expected number of deaths (e.g. extrapolating from the last 2-5 years).
This metric is independent of testing capacity and malicious actors like politicians just outright lying to the public to try to save face. You can "hide" dead people, but doing so is much harder than hiding COVID-19 related deaths.
You can't conclude from this metric what the source of all these extra deaths are, but if they are not caused by COVID-19, every alternative explanation I can think of is even worse than a global pandemic.
https://ourworldindata.org/excess-mortality-covid
https://www.economist.com/graphic-detail/2020/04/16/tracking...
https://www.ft.com/content/a26fbf7e-48f8-11ea-aeb3-955839e06...