Do you think polybius is a credible source about how democratic the roman republic was

Polybius is considered a historian whose work could not survive complete, since his form of writing, so complicated and using complex forms of language of his own time, leave only the scholars to manage to unmanage their manuscripts. His successes were to try to see the story objectively, not be sensationalist and seek to record the facts without drama, and with much truth. He is a serious and sensible historian, seeking to understand and make the readers understand the events he writes. His sources were mostly written; for his books ranging from 264 to 220, were essential. In the most important parts he recorded, from the year 220 onwards, he always consulted Greek and Roman writers. He was probably the most reliable historian who spoke about the history of Rome.