There are a couple of Mafia history series that one can watch. I watch them all. However, their information runs from outright falsehood to barely correct.

For example, one of them still insists that Bugsy Siegel named the Flamingo after Virginia Hill. Neither agrees on whether it was Profaci or Genovese behind Anastasia's murder or even mentions the other. They confusedly weave a tale during the 70s and 80s of who ran what family. There are some significant events that are not mentioned at all depending on what series you are watching.

So, I watch them for their entertainment value.