Actually, now that I'm thinking about the concept of revolutions:
Many, many (probably most) revolutions/toppling of governments fail, either because they don't have the ability (military strength, finances, support, etc.) to meet their goal, because their goal is unclear to begin with, or because they can't maintain their success once they've reached it.
January 6, 2021, for example, was a small-scale attempt at overthrowing the U.S. government--but they didn't have the ability to succeed at killing members of the U.S. Congress or stopping the vote to ratify Biden as the new president.
In Egypt, they did manage to depose Hosni Mubarak, and the Muslim Brotherhood then took power, but they was removed from power by the military about a year later, and the current leader, el-Sisi, has shifted the Egyptian government back towards authoritarianism, which is at least in part what the original protests were about.
Many revolutions in stories end with them taking power (just as many romance novels end with them getting together), which is fine, but if you want to write past that, think about what actually makes a post-revolution government succeed or fail. Is it disagreements about who should be in charge or the type of government? Is it other political infighting? Is it the lack of an effective, respected leader? Is it a lack of ability to provide civil services? Is it lack of support by average citizens? Is it a slight towards authoritarianism?
But also think about the impacts of the revolution itself, especially if it was violent. Has infrastructure been destroyed? Who has died? Are services still being provided, and if so, is the provision of those services equitable?
Let's say the revolution in your story ends with a grand battle in the capitol building--can they still use that building to legislate from? Where do people literally go to work the next day? Do necessarily files still exist?
Are civil servants willing to work for the new government? Can they be trusted?
Who from the old regime is still around, and what happens to them? Do they go to jail? Are they banned from working in the government? Are they needed in the government because they make up the vast majority of the institutional knowledge? Are they likely to form an insurgency to try to take back the government (see: the Taliban)?
Is the revolution tied to a specific ethnic or religious group, regional group, caste, etc.? If they were previously marginalized or shut out of power, do they implement oppressive or discriminatory policies against the previous ruling class (e.g., exclusion of many Sunnis from Iraqi politics/government following de-Ba'athification)?
Will the revolution spawn (or continue) an ongoing cycle of violence?