I've never thought about trademarking a blog or newsletter name. What about owning the domain name.? Does that give me any protection?

Or registering a DBA? What advantage would there be to trademarking unless you were going to use it for merchandise or something similar?

And even then, does it count if you can prove you had it first? Thanks. As I said, I've honestly never thought about this, and I've had four blogs before I built my Substack newsletters.