Books similar to On The Beach by Nevil Shute

Hello! Everyone was so helpful last time, I decided to see if anyone knew of books similar to On The Beach by Nevil Shute.

On The Beach is a 1957 post nuclear apocalypse book that deals with the story of the last people trying to contact anyone else alive while lethal radiation moves to cover them in Australia. It ends with >!time running out, and everyone dealing with coming death in a different way, including suicide via government provided pills to avoid the radiation sickness leading to inevitable death.!< It touches other genres like tragedy, a little dystopia, and a bit of alternate history (though at the time of publishing it was actually set in the future). I'd prefer something that doesn't have a happy ending.

I hope I've given this the right flair. Thank you!