R.I.P. Scout26
Folks are very inventive
I'm not an especially brave man. But, if I were you and had lived my entire life the way you have, I don't think that the death I just described to you is not the one I would choose.
People have tried to commit suicide by cutting their own head off with a chainsaw.
Wasn't that guy mostly successful? (As in like 80% severed, but 100% dead, I think.)
There's no need to get inventive in severing one's own head. Hanging and the guillotine are well-established methods, and can obviously be done solo.
Fabricating a single-use guillotine would unambiguously demonstrate one's dedication to the task...