You might be; from the UK's Crown Prosecution Service guidance website[1]: "Involuntary Manslaughter. Where an unlawful killing is done without an intention to kill or to cause grievous bodily harm, the suspect is to be charged with manslaughter not murder.". From Wikipedia[2]: "In English law, manslaughter is a less serious offence than murder."
[1] https://www.cps.gov.uk/prosecution-guidance/homicide-murder-...
[2] https://en.wikipedia.org/wiki/Manslaughter#England_and_Wales
The GBH (Grievous Bodily Harm) is crucial there. The intent only needs to be GBH which is way easier to prove, for example weapon use. The prosecutors don't need to prove intent to kill, the death is evidence that you killed somebody (except in the rare cases they can't produce a corpse, for which they have to do more work)
The death is evidence that you killed somebody, but you can still be "innocent of murder" (and guilty of manslaughter instead. In the UK). That's why there are so many varieties of manslaughter, to determine how culpable the person is, whether they were negligent, whether they were comitting another crime, etc.
Also, AIUI Death of the Author is not about whether their beliefs mattered to understand the intended meaning, but instead whether "intended meaning" is even a thing anyway. No need to understand it if it doesn't exist. I prefer in other contexts not to try to guess intentions when I can instead look at the effects and it seems to me our law and practice agree.
Notice for example that while proving attempted murder requires that you wanted the victim to die, murder does not. The fact that they are dead satisfies this aspect of the crime, you aren't innocent of murder just because you didn't intend that the victim would die.