Agree.
If it’s beyond all doubt, 100% for sure, then the execution should be swift and via hanging.
Hanging by breaking the neck is still the best way to execute someone. All these modern day contraptions and ideas NEVER work out as advertised: gas chamber, electrocution, lethal injection. A firing squad is a mess and potential problem for those on it.
I think you mean “breaking the neck by hanging”, but no matter. Hanging is far from foolproof, and a botched hanging can be pretty gruesome. I don’t think there’s any method of executing someone that can’t be screwed up.