I'm opinionated in the sense that the only "legitimate" government would be one that is chosen democratically and acts in a particular manner.

And I'm particularly not saying that there is or must ever have been some particular "legitimate government" for every piece of land. I'm just saying that when the US went in and kicked out the Taliban, they definitely weren't making things worse from a lot of perspectives. They ultimately weren't able to solve all the problems, but that is a different question. The 20 years have largely been better than the years under Taliban rule.

IIRC, historically, the tribal settlements in the country never had a ton of interaction with each other due to the terrain. I think it's a great example of modern borders not making much sense given the interactions of the population.

There have often been buddhist, muslim and other kingdoms or larger military organizations in power in Afghanistan.

It's not that the borders don't make sense, it's that the area as a whole is hard to rule and it's hard to pay for that ruling. Currently one could argue that the medieval kind of "political technology" used by the Taliban is superior to the democratic political technology, for this very reason.

Re-watched the video I was misremembering, and they're iterating exactly what you mentioned. I learned more about Afghanistan from this than anything in the news for the past two decades -- https://www.youtube.com/watch?v=Ab9zK8yT4_Y

Also the win condition of the government and government forces was to keep order in all of Afghanistan, guarantee the rights of women, and generally promote economic progress.

The Taliban's win condition was basically to inflict just enough damage the former condition would be impossible. Their troops are not far removed from criminals themselves: they loot, rape and torture.

I mean, we've seen conclusively with leaks like Collateral Murder -- there are no winners in war.

No, there weren't. The one king which ran off to Italy was somewhat moderately legitimate, and moderately popular, but not enough to survive having his key people assassinated, nor to gain meaningful foreign assistance (USA denied his plea to save his ass from communists.)

It were Britishers who started this mess 140 years ago, and they must be the ones to fix this.

The British have no capability to fix this.

The way to fix this is to return the country to city states. No central ruler.

Then the city states go fight each other. Or somebody assembles a large enough militia to loot one city after another. Or multiple city states band together and lord it over others.

* error above, it's been 180 years ago

And since then, the country effectively had 180 years of slowly going civil war without much interruption sans for the few decades under king