if you’re rejecting the conventional consensus, then when do you think was the cultural and economic zenith of the empire? i feel any alternative answer has even more problems

The cultural and economic zenith of the roman empire is the wrong question here. The height of well being in the antiquity period for the Mediterranean adjusting for expected economic growth given the passing of time is more like it. So maybe the period right before the first greco-persian war.

it’s verified by shipwreck data used to calculate economic prosperity in the empire

also, you’re just mythologizing roman “democracy” as if it was not still a brutal imperial state—for most inhabitants of Rome’s territory, the transition from the republic to the empire changed exactly nothing at all.

It's also a serious oversimplification to imply that Rome was a stable constitutional republic for centuries, and then Julius Caesar crossed the Rubicon and ruined everything. There was continuous tension within and between social classes, other Italic peoples, cities in Magna Graecia, etc.

That is very much not my claim. The Roman Senate certainly had a ton of issues with representation and you also have the mad actions of Sulla etc. But it was a candle for democracy which ended up extinguished.

Honest question; I really don't know the answer despite reading a lot of Livy, Plutarch, Suetonious, & Cicero (among others): Was "democracy" even a concept the Romans recognized in connection with their republic? They feared tyranny and monarchy, to be sure. But my sense is "it was Greek to them"

Oh you are certainly far more well read than me then. But I think it's just obviously better on average if a larger group of people makes decisions by vote than if a single person makes decisions due to birth or violence. Regardless of whether they had theory on why it was better.

*I* certainly agree with you, and think that, aside from his writing style and purely military genius, there is little to admire about Julius Caesar, or most of the emperors who followed But I have a hunch that Romans, seeing how unstable most Greek democracies were, did not try to emulate them.

the roman system explicitly considered the elitism as a feature, and compared themselves positively to greek democracies as being superior due to being less representative of the masses.

you’re also ignoring the actual bulk of people who lived under the roman state, who were not roman citizens and experienced roman government as appointed governors tasked with extracting as much money as they could from the province, often literally using the same bureaucracy as the old kings did

GDP was almost certainly higher in the Antonines. Wellbeing was almost certainly higher at almost any point of the dark ages excepting the violent fall of the empire or the plague. Far far better to be a medieval serf than to be a slave of Rome or a pauper who has to compete with slaves for work.

“far far better…” why would that be the case? like can you name one luxury enjoyed by medieval serfs that roman peasants lacked? because in the reverse, the answer is “baths”

more than that, the actual answer is “trade and money”, which means that a farmer in the high empire has more reliable subsistence than a medieval peasant due to the ability to specialize and sell their surplus, relying on the market to provide what they don’t make themselves.

the farmer of the antonine period is connected to a broader market than the medieval peasant, and this extends even to regular people, not just elites—we’ve found coinage in small farms in Britain, alongside pots manufactured in north africa

And there were certainly issues with slavery and poverty in the senatorial period as well. But I think the period before at least wasn't a tyranny where emperor's profligately spent on places, circuses and fancy columns between credit crashes like that of Tiberius.