In regards to other dictators, I'm not sure why you're only looking at post-Cold War history. What's most interesting about this period is the amount of failure by the USA to effect regime change, despite very clear evidence of such attempts, both against dictators and for them. We even have the interesting case of Haiti, where the USA supported a coup to get rid of president Aristide in 1994, then they led a UN-approved military action to re-instate him in 1998, then supported another coup to get rid of him in 2004. After the first coup, a military junta was installed, and the USA was one of few countries which traded with them. You also have US support against several islamic populist leaders in various Middle Eastern and North African countries, typically preferring secular military leaders instead - often leading to either protracted civil wars or to brief regimes that couldn't hold power. You also have a series of attempts at regime change in quasi-democratic countries, ostensibly for more democratic leaders, that failed - leaving uncertainty on whether those that they attempted to prop up would have been better or worse; the clearest example of this is the attempt to install Juan Guaido as the President of Venezuela after a deeply controversial vote.

However, I do think you're generally right - even under a more relaxed definition of what does or doesn't constitute a tyranny, the USA is clearly one of the first non-tyrannical states, at least among those that still exist today. The UK had a mostly-democratic ruling system for even longer than that.

On the other hand, if we define tyranny to refer to any state in which elections are restricted to a relatively small subset of the population, then the USA or UK are not that early. Voting in the USA was largely restricted to male property owners until 1840. Many other countries had adopted at least universal male voting by this time. The UK was even later to pass this standard.