I always believed that "Double-the-Pain" will happen before ZKK. It is the start of Zoro's final big plot(s) in Wano. This Grim Reaper, Zoro receiving more damage than should be possible for any person in One Piece, it's going to lead into a new development, that's the way it works.
Zoro receives Double All the Damage ----> which leads to "x" happening, because there needs to be a point to the plot, it's not just about incapacitating Zoro or giving him endurance feat.
Zoro receives Double All the Damage ----> which leads to "x" happening, because there needs to be a point to the plot, it's not just about incapacitating Zoro or giving him endurance feat.