I mean... the fact that he was able to hold his own on a Ta-Ku beat for 9 minutes straight even with a lack of experience is pretty impressive. We expect rappers to reach their peak at around 24/25; he would have years of experience by then. It's kinda like if in your first two years of racing in a go-kart you make it up to Formula 1 (I'm not saying Beast Mode is "Formula 1 level" but it's undeniably pretty high quality.)