They are man made estimates. 2020 numbers were fudged completely. So if you are saying they were close in 2021 then you have to say they used a scientific method for which they had none. Same with 2022. They did not know if COVID would mutate or not. Estimated deaths before COVID were easy. Basically they were based on death rates with adjustment for birth rates and average life spans.
A reduction in 2020 estimated deaths was impossible. No excuse was given but they were were most likely adjusting for their overestimates of 2016 - 2019. aka fudging.