I can't refute how much better and lyrical this album could've been (imagine if Kendrick actually brought the same consciousness he had on his solo projects). The fight for Equality and equity of race could've fit perfectly with the theme of the movie (where the bad guys, in a nutshell, want to use the country's power to help Black people take control around the globe).
But I still ought to say 6/10 might be too low. I think you always under value Kendrick's recent projects as you compare them to his best works of art (like Pimp A Butterfly), which then leads MOST music you hear nowadays to be hard-capped at a 6 or 7 out of 10 easily.
I get how thorough you are, and how you're really expecting better, but imo, the project is really great. It fits perfectly with this "Next-gen Africa" vibe, where the beats are very Drum-based, while mixing in distortion and metallic percussions and basses. Also enjoyed how there were some actually AFRICAN artists on the project and not just black Americans.