Thanks for the clarification. I actually had the Big Five in mind - somehow I confused that and MB. Even there, I don't really have any idea if Big Five is "true" (stable and/or predictive) or not, I'm really just listening to Jordan Peterson here.
Before you invest in the Big Five, you'll want to check on how much it can change your posterior odds, and compare that to results of investing time and money into other approaches.
I'll edit the post above.