Tupac is honestly overrated as fuck. He isn't that great lyrically.
I can point out at least 10 times where he rhymes, Memories, elementary, Penitentiary. That's not really a big deal but I mean come on, don't use the same rhyme multiple times in different songs..
His flow is alright, the meaning behind his music is what makes him decent.
He is not the best rapper of all time, he most likely isn't even in the top 5.
Go ahead and hate my opinion all you want, I don't really care.
My favorite song by him would be Hail Mary.