Can't quantify art.
Like in the Graffiti world, Mr. Brainwash is bullshyt cookie cutter BS but if you look at sales and money and sheer number of works produced he's probably close to the greatest artist ever. But really Banksy shyts all over him. And Picasso who isn't in that world but they arguably occupy the same "drawn art" space shyt over all of them.
So it's all subjective. You can't even argue who is better because it's all in the beholder. All I gotta say is make sure you know your Biggie inside out before making this comparison. I grew up in his era so I knew his music from its inception and I grew WITH his music. Consuming his music in hindsight you miss so much context of the world he was in and the full impact of his music.
Like you wouldn't know how big his music was. How he crossed over without hurting his street persona. And besides that, if you don't really pay attention to his hooks and flow, you won't really understand how freakishly good his rap was. Everything he put out was butter.
It's art. I can't explain it. He's still light years ahead of dudes. LIGHT YEARS. Just analyze the shyt so you're talking from a position of knowledge.