Should you get your "brand" trademarked?

I have, I guess you would call it a brand - I create video courses.

I have always thought that trademark wasn't necessary for small business - just make sure you have the domain name, the names on social media platforms, etc and nobody will bother taking the name.

However I recently read that Instagram changed the name on some business account in favor of, I think it was the British royal family. (found the article: https://www.cheatsheet.com/entertainment/prince-harry-meghan-markle-instagram-username-stolen.html/).

Is it worth trademarking your "brand" name to avoid things like this - even as a rather small business (guess you would have to trademark it worldwide)?