I think you might be looking for stories that start from a really dark place but build toward something brighter. The request is pretty specific, and honestly, that combination—suicide and a hopeful ending—is a tricky needle to thread in fanfiction. It veers heavily into the 'angst with a happy ending' and 'recovery' tags on platforms like Archive of Our Own.
From what I've come across, you'll often find it in time-travel fix-its or dimension-travel AUs. Harry doesn't necessarily stay dead; the act is a catalyst. For instance, a story might have him wake up in his 11-year-old body after that choice, forcing him to rebuild with foresight and a different support system. The hope comes from the second chance, not the initial act.
Another path is through heavy magical realism or afterlife exploration. I vaguely recall one where his 'death' was more of a sacrificial ritual that shattered a prophecy's hold, and he was remade through phoenix magic or something similar. The hopeful tone emerged from the community that formed to help him heal afterwards, focusing on found family.
You'll have better luck searching tags like 'Suicide Attempt', 'Recovery', 'Hopeful Ending', and 'Healing' rather than a specific title. Be prepared for a lot of heavy emotional lifting in the first few chapters, though.