People who want to win at street fights should read the art of war. Taking down a drunken friend or some idiot is very different then taking on thugs on the street. I believe that martial arts are only applicable to the former the latter requires more of different approach like (groups, weapons, ambush) generally how gangs get started, and generally not something I’d recommend for long term health.
Biggest lesson I ever learned from martial arts: A very good amateur boxer on his way up gets out of his car, approached by two guys telling him to give them his wallet, thinking that he could easily dispose of them he attacks the first guy while the second guy takes out a knife and stabs his in his spinal column. After surgery and rehab he was told he would never walk again.