I've been thinking of the hyperactivity in this way:
External: Classic ADHD
Internal: Inattentive presentation of ADHD
I'm not physically hyperactive, and in fact I'm usually a pretty low-energy kinda guy.
But nearly always, my mind feels like it's constantly racing, even if I'm not thinking about anything in particular. It's like little pings of micro-thoughts, constantly, over and over the entire day, making it hard to focus on anything, unless it activates Hyperfocus 😂😮💨