An agi won't need large knowledge banks to function.
If it has intelligence it should be able to "create" or "invent" in the absence of data knowledge.
Quality may vary. It would depend on some different factors.
But it should be able to create novel solutions. Just like a lot of animals can.
"Play" is often considered a sign of "sentience" in animals.
An agi that participated in behaviors for fun with no other advantage could possibly be a marker.
This assumes emotional components to agi. Which I personally believe is 100% necessary for sentience.
I also agree with you tho. That it's no where near to existing and I personally think it's not possible.