You know, I was really thinking about this one but it just occurred to me that, even in spite of the fact I'm bringing up a Christmas film with some minor religious tones I feel like Frank Capra's "It's a Wonderful Life" might actually capture the tone of reminding people that it's better to be alive than dead, let alone not exist at all.
And honestly you could make the argument that there is some existential tone to that film for one reason by the time it reaches the third act where George Bailey actually considers jumping off a bridge to kill himself only to find his guardian angel nearly drowning, goes into save him, and then his angel shows him what his life would be like if the world existed without him and his hometown would turn into a literal shit hole filled with vice, the many people who he changed for the better would be miserable, and the very man that he sought to keep from owning the town would have allowed the ruin to begin with.
I don't think this moment would have been referenced later on in popular culture like say... Rugrats, Simpsons or Tiny Toons. There's a reason why that film had such an impact on everyone at the time and still does to this day since it's such a timeless classic.
As for the situation OP speaks of... suppose that you have a Wonderful Life scenario where even if the character sees this vision and goes through with the act. You have two hypothetical scenarios that could happen after the fact:
1) The antagonist of the Wonderful Life plot gets his way, and the characters who have been impacted by the main character would be forced to move out of the town and yet, still be better people and have a downright bittersweet ending.
Or 2) Because of the protagonist's actions, influences the very people he has saved come together to fight against the antagonist of the Wonderful Life scenario and save the very life that he built up for them and honor the very values that he has upheld.
Personally, if it were me being the writer... I'd probably pick the latter outcome. Even without the religious or holiday tones you still have the positive outcome at the end of all the insanity that would ensue after the character's suicide and ultimately he would leave behind a legacy and the antagonist still loses. I feel like this outcome was also played out in a slightly different way in One Piece as well with Chopper's mentor poisoning himself and willingly ending his own life against a tyrant who ended up controlling the town's doctor's as well, only for Luffy and the Straw Hats be moved by Chopper's back story to fight for him and the impact was not only felt within the arc but the overall story due to Chopper's decision to join with the Straw Hats.
That's my two cents on this scenario and I think as long as this formula is kept in mind, then you could take it in a couple different routes.