What was the difference between Roman and Athenian governments?

Athens and Rome have had many governments throughout their history. I will assume that this question is referring to Classical Athens in the fifth century BCE and the Roman Republic.
While both governments were republics, meaning there was no king and the (male) citizens had a say in their laws, there are some marked differences between democratic Athens and the Republic of Rome.
First off, Athens was a direct democracy. This meant that citizens voted directly on issues, instead of having members of the government make the decisions. Any adult male citizen had the right to present issues and vote in the assembly. This process is not unlike voter initiatives today. If enough votes for a new law are cast, then it becomes part of the legal code.
The Roman Republic, on the other hand, was a representative democracy. Like Congress in the US, elected leaders make the important decisions, not the rank and file of the citizens. In Rome, a citizen voiced their opinions through the use of elected senators and magistrates.
When it came to political leaders, the Athenians picked theirs by lot. Any adult male citizen was eligible to serve as one of the nine council presidents. The Roman senators were voted on by the citizens. They had to campaign for office and run for election. Rome had separate councils for upper-class citizens (patricians) and lower-class citizens (plebians). Conversely, Athens did not make class distinctions in its government (though it did have strict rules about who was considered a "citizen" eligible to vote).
The reason for the difference in systems probably has to do with size. Athens was a city-state, while Rome was the capital of a vast republic. The population of Athens numbered in the tens of thousands, while Rome had perhaps millions of citizens throughout its many territories during its height. Being a representational democracy allowed Rome to streamline the democratic process.
https://www.ancient.eu/Athenian_Democracy/

https://www.ancient.eu/Roman_Government/