I have found this document that brings together all the prevalence studies and calculates the IFR (Infection fatality rate) based on it. It is constantly updated. At the time I consulted it, there was an undercount of 1:25 and an IFR of 0.2%. Link: https://docs.google.com/spreadsheets/d/1zC3kW1sMu0sjnT_vP1sh4zL0tF6fIHbA6fcG5RQdqSc/edit#gid=0
Please have a look at the following link: ://www.researchgate.net/post/Do_you_think_that_China_was_controlled_on_COVID-19_by_using_prevention_by_force_firstly_unlike_European_countries2