Honestly the only number that 3 really “owns” is 9. 6 is its own thing, 4 takes 12, 15 is clearly 5 territory, 18 & 24 are in the 6 family, 21 is embedded in 7’s lore, 27 only reminds me of 9 and 30 is obviously a 10 multiple.
If we talking about achievements, accomplishments and sales it’s Eminem but if we talking about lyricism, impact, influence, production and skills it’s still Eminem