I graduated from high school in 1989, so this is biased by the fact that I was a kid or a teenager throughout the '80s, so I'm not sure to what degree this was just me. But I remember just taking the inevitability of nuclear war almost as a given. It felt like for my whole life the world was trapped in a Mexican standoff, and the inevitable result was the annihilation of all life on the planet. It's still a possibility, of course, but I just remembered spending a lot of time in the '80s thinking it was inevitable.
When I remember the goofy '80s stuff, it was always in stark contrast to the apocalyptic stuff. The goofiness and bubbliness of '80s media felt like a reaction to the darkness of the reality.
I don't know how much of that undertone of darkness was a shared sentiment vs. my own bias because I was a moody dramatic teenager at the time. The '80s were also the heyday of the global disaster movies, that were about the extinction of the human race. I just remember a steady stream of movies about human extinction from nuclear war, disease, climate change, comets, zombies (of course), aliens, apes, etc. People still make apocalyptic movies, of course, but it just felt like fear of extinction was more in the collective subconscious then than it is now. Or maybe that was just the kind of kid that I was? I'd be interested to hear how others experienced the same years.