i wouldn't kill myself in your situation.
first thing i would do is start lifting weights. register to a gym and start a weight lifting program that you will follow with discipline. no need to go health crazy but also eat a little cleaner.
also, sit down and write. write why you are unhappy. write what you don't like about your life, what you want to change, write what you want. write why you want it, what will it get you. get to the common denominator. then seperate the list into stuff that just can't be helped (people who passed away, mistakes from the past, etc). and the stuff that you can change. Then you need to make logical plans on how to get what you want with clear measurable objectives and timelines. write it all down.
then slowly, redesign your life and living space, relationships, habits, mental train of thoughts, take all that and redesign/realign them with the sole purpose of supporting these plans that you have. stick to it as much as possible. re-evaluate and retweak whenever you need. forgive yourself and pick yourself up to go even harder after the rare times you slip up.
life isn't that serious breh. i mean it is but it isn't...the fact you have no wife or children to take care of, you might as well go all out and be great. if whatever you've been doing for the last 40 years hasn't been working for you, maybe you should try to switch it up and go a little left with it if only to see what happens.
get your hustle on. learn to find joy in the hustle and grind of it all. pay down your debt if you can and try to be as free as you can (whatever freedom means to you...)
but no i wouldn't kill myself if i were you. I won't even tell you to eliminate fear out your life. But what i will tell you is that you need to stop being your fear's bytch. Good luck breh.