No Stupid Questions

I think your questions are more complicated than you realize.

Are Autocracies more powerful than Democracies?

If you separate the form of government from the governing, yes autocracy is a superior form of government. A dictator can instantly marshal resources to face any threat, or completely shift an entire nation, if a direction becomes clearly wrong. The reason they don't work, is because the leader is always human. Humans make shit leaders, almost always. So distribution of power across a large number of people mitigates the risks of putting it all in one.

Are all democracies are doomed to fail?

Yes. Obviously. Everything eventually fails. The Sun will fail and take the earth with it.

Is the future of humanity, autocracy? For the rest of humanity's existence?

No. Obviously. Everything eventually fails. The Sun will fail and take the earth with it. I would hope humanity (or whatever species humanity evolves to) lives past that.

but the democratic country cannot easily coup an autocratic COuntry.

CIA: am I a joke to you? Look at my portfolio

Quite the opposite. Due to systemic corruption autocracies are economically highly inefficient with low productivity across the board with all kinds of long term effects this brings. And while it might look bad for democracies at the moment, I think many of the current crop of autocracies will be short lived. In the end, economy is where it's at, and autocracies are horrible at it.

Autocracies are short-lived power grabs by certain people or groups of people. They pillage what they can, oppress who they want, and then run or fall when the walls start closing in.

Many have come and gone during our history on this planet. Many more will rise and fall.

The US is a democracy (for now), and has backed multiple coups in other countries. Nicaragua is probably the classic example, but there are many, many more. See https://en.m.wikipedia.org/wiki/United_States_involvement_in_regime_change

Autocratic countries have a small number of leaders, often one.

The goal of said leader isn’t really to grow and bring wealth and prosperity, but to never lose power.

So overall, the economics of the country would plateau, cause why risk allowing wealth to grow and fall into your opponents’ hands?

Hence why countries like Russia and North Korea rarely innovate, but just take what’s available to further entrench their country’s position.

So the only way autocracy can prevail is by brining down anything superior to it, much like what Russia is doing to the US.

"countries" are invisible lines draw on a map by someone. Propaganda and lies are a tool used by people to persuade others, free speech and freedom are a natural condition upon which humanity can evolve and prosper.

The problem isn't that autocracies are better or that they win. The problem is specifically the democracy in the U.S, which is fucked because of ignorant/lazy population and greedy corrupt politicians.