The correct answer is: a big population
The more relevant metric here is deaths per capita. And excluding micro states, the top 5 in this metric is:
1: Belgium
2: UK
3: Spain
4: Italy
5: Sweden
So I suppose what they have in common is that they are all in Europe or something.
You are correct, but we should also consider the stages of the curve. The pandemic is already in decline in Spain and Italy, the recent deaths are very low. Brazil is on a stable top of the curve, at thousand deaths each day, since the end of May. Probably it will start to decrease only in August. Brazil has 80K deaths. It will reach the number of deaths per million of Spain when it reach 130K deaths.