The checks and balances are working mostly as intended. The purpose of the system is:
- Protect the oligarchy from external threats, should any anti-oligarch politician slip by all the various election disenfranchisement techniques,
- Moderate any conflicts between factions of the oligarchy to stabilize the dictatorship of the capital.
As far as I can tell,
- Billionaires are making more billions every day while the rest struggle to get by,
- Almost all dem politicians and their wealthy neoliberal donors are doing alright despite a literal fascist party being in power.
Besides, even when someone like Mamdani gets elected, they can't effect any meaningful change because they are "checked" by the pro-capitalist legislature and "balanced" by the corrupt judiciary.
It doesn't need a reboot, it needs a complete realignment of who's in charge.

If you have even a few hours of spare time, read the Communist Manifesto and Lenin's "What is to be done". The latter one is a bit harsh and not entirely agreeable, but proposes effective techniques of class warfare.
Almost half of young adults (historically, this is the demographic that will be effecting the revolution) in the US agree that socialism is good, it's just that almost nobody is willing to do anything to achieve it because they feel alone and disconnected. Build the connections, build the communities. Join the PSL or any other socialist/communist/anarchist org near you.
More practically, learn how to operate & purchase a weapon. It might be needed in the coming years, even if just for self-defense. If history is anything to go by, the fascists who gain power are not going to stop at the current level of violence.