I think I already said this before, but there are many hints in the Castlevania games that Dracula has grown tired of constantly being reincarnated and has no interest in perusing the destruction of humans any further.
He actually points this out himself in Grimoire of Souls. In that moment, he actually seems to speak to Alucard as a father, rather than a Dark Lord. The only reason why he keeps coming back is because humanity and Chaos demand it. He has no say in the matter.
He first lost his interest at the ending of Symphony of the Night, when he finally hear’s his wife’s last words from his own son. He was probably disheartened to be defeated solely by him as well. The fact that SOTN was originally intended to be the last game in the franchise also supports this idea.
I like to think that the reason why he didn’t seem to even care by the next time he was reincarnated (Order of Ecclesia) was because he was purely being manipulated by Chaos and the crimson stone (possibly by Walter’s own personality as well,) and had lost nearly all sense of himself by then due to Chaos slowly corrupting his soul.
When he was with Lisa, he had some of the vampiric personality that the crimson stone and Walter gave him, but he was also still “Mathias,” which is where his humanity comes from. I believe this bipolar personality is why Dracula is actually respectful to servants and other beings that respect him back while still being the demon king.