IMHO he's not that deep of a strategist/tactician. He really wants these sycophants and yes-men in his cabinet.
It's a purity test. Is the House/Senate GOP fully in lock-step with MAGA? Or does the old guard have the balls to vote no on his nominees, and chicanery to keep them out, and we get a steady parade of "acting" secretaries? That's how it went last time for his Cabinet posts a few years in. Everyone was an acting secretary save Bill Barr.
Nominating RFK Jr for HHS is proof of this.