J.O.A.T or G.O.A.T (prelude)

A few times friends have asked what I write about. I get tongue tied for a bit of a second and wing out an answer.
For one, I didn’t take up writing for the love of one subject in particular. Same way none of us picked up reading so we can read only about politics. Daily we read signs, tweets, prescriptions, agreements and the likes. So, when did we come up with the idea that writers should stick with one area of specialty?
That’s how I felt but thinking about it- I understand that individuals have areas where their voices ring loud above all else. Hitting notes that readers will find both angelic and insightful. Just picture an opera performance. Then picture Beyoncé on the formation tour. Different audiences, different setup- but it’s still singing right? Same with writing. Understanding the scope of reference of a field makes your voice authoritative and believable.
There are areas that I’m comfortable speaking about and that’s what these friends want to know. Mastery of the field(s) can make editors consider me competent enough for some opening they have. The offer may not be my speciality but my writing in other fields will point out that I have a voice. And with the right ideas I can inject that anywhere it’s needed. (correct me if I’m wrong).
Flowery writing is not what’s needed here.
Here I am, chin in hand. I’ve been writing for the sake of it- writing. Now I’m trying to think of what thing(s) I’ll like to write about and form opinions around. Maybe the generic thing still, but do I have an angle to it? I’m sure that there can’t be a dirge on what to write about daily. But in what area(s) can I establish a voice?
Now that’s the question to break the debit card.
(Sidebar: bad as e bad. I’ll kuku write a dirge)