a realistic 2019 after Lt. Col. Petrov listens to his computers?

The 1983 doomsday scenario works on the premise that Petrov saved the world. He didn't.
His radar screens could show a thousand missiles. Others didn't. The USSR wasn't on launch-on-warning. There was no intel support indicating an attack. Secondary and thirdly confirmation was absent.
Sorry but the whole Petrov Saved The World thing doesn't work.

That's not my point at all.
Even if Petrov did believe it, the Politburo wouldn't consider a strike because each and every other method of confirmation was absent. The KGB and the GRU would have no indications pre attack. In addition to the absence of detection by secondary missile warning systems.

This is 1986, after all. Reagan's been rattling the sabers for some time now, not to mention that the Soviet high command is probably still on edge dealing with the fallout of a small incident in Ukraine that happened just in April of that year.

Urgh. 1983D is basically ”if I like it then it wins”.

I was a contributor to the 1983:Doomsday timeline about 10 years ago. I was there when sone of the original creators left because it had gotten away from the original vision. People began writing their own pet mini-nations into canon, and though I tried to be as realistic to a post all-out nuclear war scenario as possible, I probably contributed greatly to the unrealism by making my North American nations exist as 1960s/1970s-era civilizations.

Basically, the original vision was the Northern Hemisphere was wrecked and had small pockets of pre-electricity civilization, such as the Mormons in Utah and the Native American Navajo Nation in northern Arizona/New Mexico. I turned Texas from an empty wasteland to an area with several nations (West Texas, East Texas, and a bunch of microstates). One contributor who lived in Michigan turned Kentucky into a military dictatorship run out of Fort Knox (Fort Knox should have been destroyed, and the entire state suffering from heavy fallout from the midwestern missile silo blasts). Another contributor had Fort Campbell (also in Kentucky) survive but an entire military division PULL OUT and flee east, to establish a military dictatorship/wannabe empire out of West Virginia. The same contirbutor had the Governor of Nebraska commit suicide and the people of Nebraska overwhelmingly converting to some kind of bizarre religion named Lincolnism. Someone had Mexico abandon Monterrey and build a new capital outside Mexico CIty. Yet another contributor created a Christian nation out of the Piedmont region in South Carolina and wrote himself into the story.. From there, contributors tried to create their own mini-empires, and the last original creator finally gave up and turned the timeline over to someone whose sole role seems to be to say no to everything. I don't think there's been any growth in the timeline in years, again largely because of the moderator saying NO to any and everything.

That is 1983:Doomsday in a nutshell. To the original poster, I would suggest in general:

a) the most powerful nations would be in South America and Oceania. New Zealand might be more powerful than Australia, depending on how hard the Soviets hit Australia. South Africa might be another major power, depending on a) how hard it was hit by the Soviets and b) who won the inevitable war between the apartheid government and the ANC. South America probably leads the world economically, technologically and culturally.

The northern hemiphere would be a mess, to say the least. Mexico might be a powerhouse equal to Brazil, Australia, South Africa and Argentina in a best-case scenario. Saddam may have turned Iraq into a regional power in the Middle East. Otherwise you probably have mini and micro states in areas of North America, Siberia and China that managed to avoid fallout and are at a pre-electrical/industrial level. I'm not sure if there would be a Swiss and Scandinavian nation or not, because I tend to think Europe would be a total radioactive hellhole well into the 30th century. The Philippines might be a regional power in Asia. Again, you'd have to come up with a list of sites that got nuked, then determine where the fallout went and didn't go, then determine who's left in the clean areas, THEN figure out which towns/cities/states/provinces/countries hold things together and which ones fall apart, and go from there.

Seems I am right though. You know without the whole nuclear war happening.
Take some time to do some reading on the issue - books - and you'll end up wiser and less patronising.