Given need, access to anything that might serve as string, pieces of wood, and too much time to think about the problem, most singular humans will come up with that within the year, if not within days.
That thing has probably been independently invented a hundred thousand times over. Trying to figure out who did it first is silly.
Also that is not a "sophisticated" tool at all. It's literally one step above hitting rocks together. Sharp rocks happens to be the only tool you need to make a basic bow drill.
Alloying copper with silver and lead is sophisticated. How could they have got to this without structured research, experimentation, controlled manufacturing. It’s a lot closer to our drill bits now than a sharpened bone.
But to make a drill bit of highly alloyed copper you need a bit more tools and knowledge
> Trying to figure out who did it first is silly.
True. Good thing no one is trying to do that.
Basic research is never silly.
I think it is several steps up and beyond from hitting rocks together.
You need to create string. You need to cut the wood for the bow. The bow and the string need to be the right sizes too. You need something that is sharp enough to work as the drill bit but also small AND approximately round enough to work in the bow. That also needs to be made of a material that is harder than the one you are drilling - here in this story there was some sort metallurgy involved to create the alloy, so that likely involves working with ores etc (mining, identifying, processing etc etc).
There are a lot of steps. You can't just find a random "vine" to wrap snuggly and securely around a random thing you find to use as a drill bit that is like 1cm in diameter - you'll need something of consistent size and highly flexible for the string, similar for the drill bit needs to be the right size and so on.
The next step up from banging rocks together is probably using sharp stone chips as scrapers or crude knives. Even napped stone axes are quite difficult to create and require skill, even if the raw components are literally laying around.
I suspect the average person would struggle to make fire, let alone hand tools.