Also, that scene where Captain Atom on camera eats a nuke should be his introduction to the world, a nice bit of scare propaganda to the reds. Not something like Supes catching a woman in one arm, catching a helicopter in the other with a shit-eating grin, highlight the difference between the two.
Atom is the apex of his generation, his only limitation being that he was made from a soldier and not a scientist (I like to think he could get on Doctor Manhattan’s level if he had Osterman’s intellect) and despite his creation being an attempt to scare the reds, he worsens things and during the Global Guardian’s final mission he accidentally slew one of the Russian superheroes, causing the nuclear war, only stopped when he carried out his greatest feat and absorbed Earth’s entire stockpile of launched nuclear weapons, effectively cooling off the war permanently.
Given DC's list of Russian Heroes, we have Rocket Red Brigade, the russian Firestorm counterpart Pozhar, the new Red Lantern, the Young All-Stars adjacent heroine who was named Fireball or sth, Red/Blue Trinity, Red Star, and The People's Heroes.
I'd say that the most interesting part of this is that the only ones that you couldn't retrofit into this time period would be the Rocket Red Brigade and Red Star due to the Rocket Reds being invented by Kilowog and Red Star being a Teen Titan. Rewrite the Trinity Speedsters as the soviets trying to recreate Flash/Johnny Quick, have Pozhar be their attempt at a Captain Atom, and whatnot.
The event goes well enough, with Fireball shaking hands with the Guardians and the semi-retired golden age heroes, trying to bring peace. In the background, it all gets upended by someone triggering fights between the more volatile members of the Soviet group and non-soviets. So, like Blue Trinity/People's Heroes fight and injure a bunch of the older heroes, leading to Fireball trying to stop things before she gets put into a coma. The Nukes are launched. Pozhar tries to absorb as many as he can before he falls and we see a younger Martin Stein witness this, inspiring him to work on the Firestorm project for the government (as alluded in Doomsday Clock). Atom believes that he's just like Pozhar and volunteers to absorb all the nuclear energy. The Ray and a few others capable of controlling the directions of the launched nukes help aim them at the man. Doctor Mist sighs as he says that, perhaps, the world isn't ready for a new age of heroes just yet.
Captain Atom and Pozhar are honored by their countries for saving the world. The Man of the atom and The Soviet Nuclear man prevent a great disaster, but both goverments realize that the real arms race is no longer nuclear. They need metahumans, magic, super-science, and all the crazy shit from the Golden Age. A comic book version of Operation Paperclip occurs on both sides. The Soviets and the Chinese try to kidnap as many surviving super-scientists, mages, and monsters from their sphere of influence while avoiding touching NATO/American areas. The US Government and the NATO countries try to recruit as many specialists and metahuman and etc. by preying on cold war fears as well as the idea that, if the good guys don't get with the program and help guide things, then they'll just let the bad guys do their agenda. This leads to the introduction of a young T.O. Morrow and others. Basically, 52s Oolong Island but for the Cold War and for each side.
In the meantime, we get bits of lore on other happenings. A man from the land by the name of Curry falls in love with a woman from Atlantis. A young man on America's West Coast sees his father sacrifice himself in a plane test gone awry. In the midwest, another young man sees his mother killed and his father sent to jail for it. In gotham, a robbery goes wrong in Crime Alley. In kansas, a kindly couple find a baby in a spaceship. On an island, a woman makes a child out of clay and asks the heavens to grant her life.
Doctor Erdel's teleportation works and summons a green man, the last of his kind. The Green Man melds into Earth, engaging in superheroics on the sly.
In the midst of these origin stories, The Phantom Stranger walks and tries to prevent various crisis events. However, during his off-time, he walks and sees these young people through their dark hours of their youth and tries to give them a few words of wisdom as a friendly stranger.
Somewhere else, the Justice Experience all die, except for J'onn. Making him more reluctant to engage in Superheroics until the modern age really kicks in.
I think weaving them with the evolvution of tech that will bring about the Brain, Cyborg, Red Tornado among other could be really interesting
What's funny is that those three have a prominent scientist character that works on them
Niles Caulder, Silas Stone, T.O. Morrow. You'd be able to work each of them into the stories very easily. Maybe make it so that Caulder starts off as a heroic idealist on a slippery slope. Stone is a man that gets too focused on research, but is otherwise sorta normal-ish, and Morrow just invents his damned time-viewer and keeps it a secret. The original Starman and Hourman are the most important super-scientists due to Starman working on the Manhattan Project and Hourman making the world's first known super-steroid.
You know what else could be fun would be the government trying to reverse engineer a few samples of Miraclo and the Blue Beetle drug from the '40s, but to little success. Which leads to the creation of venom and other similar drugs.
The whole project with The Ray and all that, which has been running since the '40s, yields a successful process in creating a person with that powerset, but it requires a special combo of rare ingredients. (This lets the government use the shitty evil Ray from the '00s Freedom Fighters comic as a government goon. Maybe call him something else)
The government gets some of these metahuman projects to work, but most of them aren't great. They get a Doll Man, an atomic Human Bomb, and whatnot. They want to make another Captain Atom, but can't find the special metal alloy required.
Somehow, somewhere, Dan Garret is still active as The Blue Beetle, having tricked the public into thinking he's the second one. As the modern age begins, he dies in the first year or two, before the JSA comes out of retirement.