Two things. First, don't off yourself. Life is full of bullshit no matter what but it's full of beauty too. Maybe get out more and enjoy nature, it really helps with my mental health, and gives me something to look forward to. Even though my friends were never that into the outdoors, I took them on a few trips and now they love going /out/. I have a backpacking trip planned with them in two weeks, and the anticipation is getting me through some rough times right now. When i didn't have friends to go with, i went backpacking alone and that helped a lot too.
Second, assuming you're not really gonna an hero, read this article:
https://www.nytimes.com/interactive/2018/03/22/magazine/voyages-joshua-tree-lost-hiker.html it's about someone who disappeared without a trace in a national park. Interesting food for thought. IF you really wanted to die and disappear completely, I would pick somewhere like Joshua tree. Get a rental car or hitch a ride out to a remote trailhead, walk as far as you can (off trail), and make sure not to leave any trace. If you really want to plan it out, you could even go the day/week before and plant some false trails like leaving a clothing item in a different area from where you plan to disappear. Then when you're ready, find some random hole in the rocks that you can barely fit into, get as deep as you can, and they'll never find your body.
But seriously don't do it. maybe even take a trip and scout it out though. You might find you enjoy it so much you don't wanna kill yourself :)
