Government services to the population, if any, are in shambles, all the institutions are corrupted, people probably don't trust authorities, there might be racial/ethnic tensions, inequalities are deep and rampant, propaganda from the old regime is deeply ingrained, the new government might not even have accurate data about anything about the population...

Where do you even start to establish a better, more equitable system? Infrastructure? Education? How do you get rid of the corruption when it's so pervasive? How do you build trust with the population?

Hell how do you even just keep chaos at bay when the cops were already corrupt as fuck

How do you (re)start an economy? Accepting international help might not even be safe because there definitely are "rich" countries only looking to profit from the chaos in your country to exploit your resources (if any) and your people and steal everything, even nailed down shit.

It seems like such a unsolvable problem and I'm not knowledgeable enough about any of the above to even know where I'd start the dive into a rabbit hole researching this

So this has been done before in a variety of ways, some more successful than others

The French Revolution to my recollection mostly just took over the kingdom's existing bureaucracy, which was decent, but the competing factions in the new legislature caused some problems to say the least

The Russian Civil War, when it eventually shook out in favor of the Bolsheviks, saw the new government having to build new institutions from the ground up

This was often accomplished at gunpoint and or starved millions of people and wasn't a good time for anyone

yeah :/

There always seems to be a period where Shit Ain't Fun

To use a v a s t understatement

That's the nature of change

That's very true