Running should not be your first approach in these situations. If anything, it should be either your last or second last option (Depending on whether your better at fighting or running and which one the situation calls for more at the time)
If “Just run” is your only self defence strategy, you are:
a: Betting that you’re faster than your opponent. There’s a 50% chance that’s wrong, and if they do catch you, you’re now going to be too tired to stop them from beating you to a pulp. The reason people tell you not to rely on fighting an attacker in self defence is because fighting is a direct pitting of your physicality against another person (Who is probably more physically capable than you if they singled you out as a victim). Running is just as much, if not an even more of a direct pitting of your physicality against another persons, and as such runs into many of the same problems as fighting does as a viable self defence strategy
b: Assuming that you’re in an environment that allows you to easily run away. That strategy goes out the window the second you’re not in an open environment. Put a door in your path that you need to open or even a corner that you need to turn and you’re going to get caught even if you are faster than the other guy. There are videos where people pressure test “just running” from an attacker and it rarely works
c: If you’re with someone other than yourself when attacked (Assuming it’s someone who isn’t as athletically capable as you), running probably isn’t an option
So to whoever’s reading this, you’re probably asking “If the holy grail of self defence advice from know it all redditors (Who in all honesty, most of whom have probably not run since middle school gym class) isn’t a magic bullet, what will save my ass?”
Personally, I’m a big fan of the “Be a mature adult and don’t get yourself into these stupid predicaments” technique. Common sense is bar non the most effective self defence skill
If that fails, I’m also a big fan of the “I’m sorry I offended you, can I please make it up to you by buying you another drink?” technique. A variation of this technique that can be used in more extreme scenarios is the “Here, take my wallet, phone and shoes. I don’t want any trouble” technique. De-escalation and “Verbal Judo” is a close second for the most effective self defence skill
If that doesn’t work, then your two equally dangerous options are fighting or running, and you have to choose very carefully between them based on the unique factors of the specific situation at hand