Occam's Razor, dude. On the one hand, a non-binary person killed themselves after being bullied, which is regrettably more common than it should be. On the other hand, you have an (at least) 3-person conspiracy to fake Byuu's death, not to mention get them a new legal identity since they've already publicly declared "David Ginder" to be dead.

I've presented corroborating evidence, in the form of the newspaper article. I'll admit it's not absolutely ironclad, but it would not be trivial to fake. Under the circumstances, it's more "official" evidence than I would expect from any other death of an American national living in Japan, all else being equal.

Meanwhile, in this thread, you've made several falsifiable claims that haven't been borne out. Starting with the claim that there is affirmative Japanese documentation that no Americans died in Japan during the relevant time period. Still waiting for you to back that one up. Then you claimed that the journalist didn't provide an official quote from Byuu's employer, which they clearly did. Now you're gone from claiming that we don't have sufficient evidence one way or the other to saying I should "be happy that Byuu is still alive". Where's your documentation for that claim?

You seem very invested in convincing other people on the internet that Byuu faked their death. I'm pretty sure that if I were able to produce a death certificate, that you would just move the goalposts again and say that there's no proof that David Ginder was really Byuu. (Or would you commit now to accepting a death certificate for David Ginder as proof that Byuu was cyberbullied into killing themselves?)