I've wondered about this. Like if this is a Prince-like experiment of using someone else to release songs you wouldn't put on your own albums. Not to say Keem is devoid of talent but as that post says, Kendrick wrote a whoooole bunch of The Melodic Blue. Or came up with the melodies.
The bigger problem to me is that the more he steps into that more melodic, less lyrical content, the worse Kendrick becomes at being...Kendrick. Lyrically I feel like Mr Morale is his worst album. DAMN had all types of slick shyt on it so the more mainstream sound didn't hurt him much lyrically, plus it had tracks like Feel and Fear (and Duckworth). There's nothing like that on the new album. Father Time comes close. My fear is that the days of Kendrick actually trying to RAP rap are over and he's gonna be doing this Kanye-esque vibes shyt. He's not strong enough melodically to pull that off IMO.