I am also childless, and in my case completely alone (no siblings, no parents, no relatives). Like you I am in good health at the moment but I have seen how that can change overnight.

Plus I am autistic and the State has already taken an interest in my "wellbeing". I even have a social worker now. They can f'ing declare me incompetent and institutionalize me if I'm not careful.

I have zero desire to end my days in a nursing home. Covid made them death traps and they are getting worse, not better. My mother died of Alzheimers and I saw firsthand how awful that is, no thanks.

I'm with you. When the time comes I want it to be quick and painless. If it comes down to it, there is always "eating your gun".