You Don't Know What You Don't Know; Someone Else Does

The TV show Succession apparently has a wealth consultant. This person advises on things like whether or not someone would carry their own suitcase or wear a coat regardless of the weather.

Consultants like this one advise about things that someone without that kind of wealth might never think about.

If you're writing about a place, situation, culture, or language that you aren't intimately familiar with, there is a chance that you too need a consultant. There's a change you're making simple mistakes that you didn't even know were possible.

There is no research that will give you all the knowledge that you might need.

And that's why you need readers. Have someone who does have that intimate knowledge read what you've written. They'll be able to point out your errors, you'll be able to learn from them, and your readers will be able to enjoy your story without being distracted by some silly mistakes.