By the time The Rise of Skywalker rolled around, The First Order merged its forces with Palpatine’s to form The Final Order, and it looked like this dictatorship would finally take control of the entire galaxy and rule it as a Sith Empire.
Fortunately, the remnants of The Resistance were aided by last-minute reinforcements and were able to bring down The Final Order for good, meaning the galaxy is once again at peace… for now.
As seen in The Force Awakens, The New Republic was eventually wiped away entirely once Starkiller Base destroyed its capital planet, Hosnian Prime.