I wouldn't be surprised if this article was AI generated. Ignore it. It does not add any value. Just show your work. And if you have no idea how to design your portfolio, make it as ugly as possible and then call it brutalist.
Are you the writer of the article?
I think letting your own style and taste get through is better than showing range. You probably know what you like best, and you're probably really good at making just that, and there's probably an employer out there that is looking for precisely that. The risk or showing range is that that taste and "peak" never really gets through. Nailing a job that is looking for your taste instead of your range is a sure better way to a faster and more fun career.
You're building from scratch or are you updating it. Curious how you nailed being a 'freelance graphic designer' without a full portfolio. Most of them are quite famous but a good portfolio doesn't have to look cool, the primary focus should be on the work instead. So, don't stress it too much if you trust your own work.
Most freelancers start off with working to old employers or with people in their network. You'd be surprised how long someone can go without a proper portfolio so I believe it is better to hold of judgment here :)