In my research into the Second Temple Period, I have collected material on Philo from two books. I am making these scans temporarily available at:
https://jwstudies.com/This_world__chap_10__Philo.pdf
https://jwstudies.com/Reading_Romans_in_Context__Philo_.pdf
These pages illuminate Paul's environment and they provide the contemporary context for some of his reasoning.
I was particularly taken with Pages 125-126 of the book, "Reading Romans in Context" (PDF file pages 20-21), which show how Paul misused Scripture in order to arrive at his predetermined conclusion.
I have not marked up these files. The material is not difficult to follow.
Doug