A good-hearted techie becomes a singular ruler of the country. By some luck they aren't immediately deposed due to their inability/unwillingness to play internal politics. Soon they discover that just keeping that country from getting invaded by neighbours, or economically sabotaged by others, requires getting ready for war and nurturing - or even employing - the ability to project force.
Say they think "fuck it" and through smarts and few surgical strikes, they take over the world. We have one government on the planet, with one ruler. But how long will that survive, given that there will be people sowing dissent? How long will it take before the governance either dies, or turns into a dystopian story straight from Black Mirror? What will happen when the Mars colony decides to declare independence (a tech person is in charge, there will be a Mars colony)?
Or another scenario - let's say multiple techies take over the world; how fast will the planet turn into a glass desert, forever testifying to the holy war between Emacs and Vim, or JavaScript versus basic sanity?
My point is, I don't believe techies are suited to rule humanity. I don't believe anyone is. And I have no idea if a civilization-scale governance that is stable, universally good, and that would survive more than few decades, is even possible.