You should compare Sweden to its closest neighbors, not to all of Europe or all of the World).

Countries geographically close to each other are more similar than countries far apart. Therefore you can more readily attribute the difference in death-rates to differences in policy.

And use Occam's Razor: The simplest explanation for the 10x difference in death-rates is most probably the correct one: lack of lockdown. It just makes (common) sense.

What is your explanation for the 10x difference in death-rates between Sweden and its closest neighbors? Do you have a simpler explanation than the lack of lockdown?