Language is not decoration. It determines which groups of people can locate each other.
Specialists have this solved. A herpetologist can find other herpetologists, and there will be a journal, a conference and an argument already in progress. The word does the work: it names a practice, implies a standard, and points at a door.
Now try it for the other kind of person. What do you call someone whose actual distinguishing feature is that they know a serious amount about four unrelated things and are currently learning a fifth?
The available vocabulary
Jack of all trades arrives with its own insult attached, and everyone knows the second half of the phrase even when it is left politely unsaid.
Multipotentialite and scanner come from the self-help shelf and sound like conditions.
T-shaped is a diagram from a consultancy deck. Nobody has ever been introduced at a wedding as T-shaped.
Autodidact is closer, but describes only how you learned, not what you do with it, and carries a faint suggestion of having done it alone in a shed out of stubbornness.
Curious is true and far too weak. Everyone thinks they are curious. It is the personality equivalent of claiming a good sense of humour.
What a good word would do
It would need to imply study rather than dabbling, and practice rather than personality. It should suggest responsibility, because capability without care is the failure mode of this whole type. It should be pleasurable to say and mildly ridiculous, so that using it stays self-aware and nobody starts a robe budget. And it should be gender-neutral in a way that requires no explanation and admits no second version.
Wizard does all of that, which is either a genuine linguistic accident or evidence that the archetype was always describing something real. Either way, it is the best available option, and it has the advantage of already being understood by everyone.
The alternative is what we have now: several million people with the same habits, no shared word, and no particular reason to think there is anybody else out there doing it.