Try adding this customdata to your:
px.sunburst(custom_data=["country_txt", "year", "Attacks", "killed"])
And then change the hovertemplate like this:
fig.update_traces(
hovertemplate='country: %{customdata[0]}<br>'
'Year: %{customdata[1]}<br>'
'Attacks: %{customdata[2]}<br>'
'killed: %{customdata[3]}<br>',
)
You should get:
