It is unquestionably the case that Soviet authoritarianism and disregard for safety is to blame for what happened. But one thing that is often forgotten, but I think the show highlights, is how well the aftermath was handled.
Yes, Pripyat should have been evacuated earlier, and yes, they should probably have notified the rest of the world sooner. But think of this: the Soviet Union mobilized 500,000-750,000 people to clean up the enormous exclusion zone. They got thousands of men to don full lead suits (that could only be used once) to run out on a roof for 90 seconds each to throw off radioactive rocks one at a time. They built the enormous containment structure in just a few months, arguably the greatest feat of civil engineering in history. One of my favorite scenes in the show is when Legasov says he immediately needs 5,000 tons of sand and boron to cover the core, and Scherbina basically just walks off and gets it for him (along with a full fleet of helicopters to drop it).
All of this was necessary, and they did all of it, no matter the cost. This was unquestionably a real strength of the Soviet Union. Can you imagine that the US would have been able to respond like this? Either today or in the 80s? I can't. With the exception of wartime mobilization, I can think of almost nothing else that even compares. There are few (if any) societies in history that could have done what the Soviet Union did in response to Chernobyl. In a way, the world is lucky it happened there and not somewhere else.