Like many here and of a similar age around the early to mid 80s, I had a morbid fear of nuclear war. I wasn’t allowed to watch Threads when it was broadcast though I vividly remember sneaking a peek on the TV in my bedroom, just as the weapons detonated and being so utterly terrified as to be physically sick.
I overcame that fear by reading as much about the subject as I could; everything from first hand accounts of Hiroshima and Nagasaki through to works of fiction and docu-fiction.
One book in particular helped enormously: ‘Warday’ James Kunetka and Whitley Striber: Warday on Wikipedia
I watched ‘Threads’ as an adult. I wouldn’t even go so far as to call it a ‘post apocalyptic dystopia’ as dystopia suggests at least some form of societal structure and organisatio. There isn’t a shred of that in Threads.
It ends utterly without hope.