Well there's your issue. But no, he isn't, he's actually used as a plot device by Beyond himself to help Dio and Joji. Maybe if you consider JDC novels into that, but that's its own canon unrelated to Jorge's canon. It's kinda like, you know how like Metroids show up in Kid Icarus sometimes? Kind of like that, they're the "same thing" but completely unrelated to the other canon, it's more so a "hey hey look it's that thing you remember, cool ain't it?".
Tsuku is a dude who appeared in other meta novels that came before JJ, he cameos in JJ tho a few times but that's kind of it.
Also it'd be wank anyway, he isn't outer even in his own books. If you want to be exceptionally generous, he'd be low tier 1 at best,