Not so sure about all countries. We didn’t do a lot of testing at the start, a lot less than other comparable countries, and we have still ended up with a load of hospitalisation sand deaths. Countries like Russia and China I wouldn’t believe their stats as they are totalitarian and stats say what the man wants them to day. Others like Brazil and India will not have the infrastructure to accurately report even if they wanted to.
But the European countries I would expect to have reasonably accurate figures, although it will be the excess deaths figure that ultimately will show the effect of the virus in each country and it will look bad for us.