I'm over 30 and can still read this, but I have an advantage since most of the terms originated in AAVE (excluding baka; I can thank being a teenaged weeb for that). I'm guessing gen x and any of the boomers left alive would be having translation issues.
I'm Gen X and not a fan of chat abbreviations but I was mostly just lost on "bussin'" (so I looked it up on Urban Dictionary). Not sure if "I vibe it" is like a form of "vibing" or more like "I'm feeling it" (or something else) though.
Ah you think darkness is your ally? You merely adopted the dark. I was born in it, molded by it.
A more literal translation would be "Wait, you think darkness is really cool? You actually just leaned into (or stole) the darkness, you idiot. I'm serious. Not to brag, but I feel the darkness strongly, no lie."