I’m not going to get into the weeds on this, but running isn’t that different from weight lifting. The same principles apply. You need to consistently increase your workload, either through volume or intensity. Allow for adequate recovery, eat right, and if your training for something, the rules of specificity apply.
That’s the big brush strokes and if you follow that you will get better.
People like to act like running is this crazy mysterious thing. Or they like to say that some people can just do it and others can’t. And, while there is a genetic factor, you are not handicapped by some omniscient force saying that you cannot improve your run, unless you have a medical condition.
Don’t let fads and bro-science hold you back. If you want to get better at running, you can, and chances are you have a rough idea how.