Even if you disagree with them, Trotskyists are not tankies, simple Marxists aren't tankies, leftists curious and exploring different theories aren't tankies, and ffs anarchists like myself are not tankies.
I feel like "tankie" indicated a very specific worldview at one time, but it's been used lately a lot to mean things like "doesn't agree with nations supporting oppression and inequity up to and including genocide" -- which is drastically at odds with how I've seen the term used in the past, no?
As an ML, I believe that the best course of action is defined by material conditions, such that there is no universal set of policies that is best for every country. Countries like the USSR and the PRC came into being with extreme poverty, little industry, and surrounded by enemies, and some of the measures that they took were necessary for their survival and development, and would not be necessary for other countries with different conditions. But other measures weren't necessary at all.
Both countries eventually transitioned from a more militant leader to a calmer, more civilian government. In both cases, it would've been better if it happened faster. But there are also plenty of governments around the world that did not take such strict measures to protect themselves and were defeated as a result, often with devastating consequences, and navigating that is a challenging question for everyone, not just for MLs.
There are plenty of countries that did not take strict measures to ensure their security and fell to CIA coups, sometimes resulting in fascists coming to power and committing mass slaughter while securing their power for decades. Mohammad Mossadegh of Iran, for instance, was a true believer in democratic ideals, and the result was that he did nothing as the CIA infiltrated the country and ousted him, which led to decades of the shah's secret police hunting down and exterminating the Iranian left, which led to the situation there now.
So, it's tough to say. On the whole, I believe that the revolutions in Russia and China did more good than harm. But the skillset you use to win and secure a revolution is not the skillset you need to manage a country during peacetime, and which of those is more important at a given time is driven by external factors.