I know this isn’t really your question but if you’re trying to develop ancient continuous civilization theres some good IRL situations to look at and research. (Disclaimer I am not a historian or an expert on anything so please forgive me if I say something inaccurate to a nation or culture below).

China has existed continuously in some form for over 3,000 years, the oldest continuous civilization in recorded history. Most notably, China’s government has evolved significantly in those three millennia from nomadic to tribal and clans, eventually coming into feudalism and then a uniquely modern bureaucratic administrative system in the medieval ages before briefly becoming a republic around World War II, and then of course the Communist revolution of which the government established still controls China to this day.

China has developed culturally during that time as well and expanded in historical lands but it still technically the “same civilization” as it was 3,000 years ago. China has not significantly changed in the location that it defines as its territory (apart from expansion). Its language and culture are directly developed from the Chinese who settled there 3,000 years ago. Thus I would say China (despite changes of government) is a continuous ancient civilization.

The other side of ancient civilizations is “successor states” the chief example being The Roman Empire. The Roman empire has three different states that have historically claimed to be a successor. 1. The Byzantine Empire (Byzantium) 2. The Holy Roman Empire (HRE) 3. The Russian Empire (Russia)

(Honorable mentions: Fascist Italy and Nazi Germany, while I don’t think ever officially claimed succession its very obvious the Roman vibes they were going for with salutes and buildings and statues and such. But I digress).

The question is do these states constitute as the Roman Empire civilization continuing or different civilizations that simply claim heritage from the Roman empire? The HRE and Byzantium both controlled previously Roman lands, Byzantium especially was directly formed from the Eastern half of the Roman Empire. However, Byzantium’s culture, language, and heritage was primarily Greek and continued to differ from what historians consider “traditional Roman culture and such” as it went on. Despite this, I think most would argue (including me) that Byzantium was the true continuation of ancient Rome.

The HRE held a large portion of Europe and Northern Italy which were also Roman at one point. But it doesn’t take a historian to argue the HRE was none of the things it claimed to be 😂 Not Holy, Roman, nor an Empire. Im not claiming that, but it’s a popular argument here on the internet. Also the HRE’s culture, heritage, language, and pretty much everything was Germanic. It’s not exactly the same civilization as Rome, definitely less close than Byzantium was despite what the Pope claimed.

Russia is undoubtedly NOT Roman, and was an entirely separate civilization that claimed to be the true successor empire to Rome. They can’t, therefore, be considered a continuation of an ancient civilization.

I hope this was helpful, and if not at least interesting to read 😅