There’s an age-old bit of writing advice that goes “Write what you know.” I’m going to turn it on its head and suggest that rather than writing what you know, you should know what you write.
The difference is subtle but important. If you only write what you know, your stories are truly limited. Maybe you’ve had powerful experiences in your life to draw from, but even if you do, can you write every word of your story with only the details in your head? If you can, is that the best story you can tell, or might it be better if you were able to add some details you aren’t entirely familiar with, but can learn about.
It’s up to you to decide if every aspect of everything you write comes from your head or not, but take the shackles off. As long as you spend the time to do the research, you can write about almost anything. What you can’t do, is try to pretend you know something you don’t. If you haven’t done your homework, it will show.