On the TOP of leadership ladder, your responsibility is always big. You have to keep your subordinate in check and listen to your subjects desire and decide which option will lead to whole nation progress.
The demon king is definitely not some kind of malevolent entity, but not entirely benevolent either, it is what this demon king is, a ruler. Objectively, Dariel is better in logistics preparation making him the best logistic officer in Demon king army, making sure their employees demands is heard and finding the solution. Also as an advisor in war, he actually has the best skill thanks to his adoptive parent teaching.
Bashubaza desire actually cloud him from better judgement, it is a narcissistic tendencies. I do hope his character will be developed as I would respond like the Demon king in this chapter.