Koko Wa Makasete Sakini Ike! Wo Shitai Shinitagari No Nozomanu Uchuu Gekokujou summary:

Nao Bruce is suffering. The university student watched as his girlfriend dumped him to run off with another man, and now he has nothing to live for anymore. As he contemplates suicide, he sees an advertisement for the Space Force a military power dedicated to protecting the planet from all sorts of extraterrestrial enemies.An idea hatches in his head he heard of the cliche where the hero tells his comrades "I'll take it from here. You go on without me." It's a perfect way for him to die while looking like the suave hero he always wanted to be seen as! There's only one issue: he's a little too competent to die on his own