Count Dankula seems to show a bit of remorse upon his defeat by Alucard in 1797, but that small piece of insight quickly went away in subsequent games. All he cares about is world domination moving forward.
My adamant working theory since Portrait of Ruin has been that Dracula's human soul moved on that day.
Unfortunately, Dracula isn't JUST Mathias. He'd spent quite a lot of time killing other vampires, absorbing their souls, adding their powers to his, never mind his singular connection to Chaos... conceivably there was quite a lot to the entity we call Dracula that was NOT human. And that would have been so evil it never would be permitted into Heaven. So it stuck around.
And if you notice in chronologically later games, Dracula gets a LOT less chatty, and when he does chat he's much more stereotypically evil. He makes borderline sexist remarks to Shanoa (claiming she must have been the one to resurrect him and she "only" would have done so so he could grant her eternal beauty, or power at his side as his consort), and in Portrait of Ruin only seems to care about getting his "full" powers back ("One day, my power will be fully revived!"), which beyond being the most generic Castlevania villain quote of all time, strongly implies that he
believes that
he no longer has his full powers.
That would be consistent with losing his human side, and with what Alucard told him at the end of Symphony: "You have been doomed ever since you lost the ability to love. / You lost your heart. Your soul. You'll never win without them. / When you lose those you love, and stop loving, you have already lost..."
If you want to believe so, there's enough there to claim that God pulled a sneaky, and by taking Mathias when he was asking Lisa's forgiveness, denied Chaos its greatest champion, leaving it forever with a "broken and dulled blade", doomed to lose forever hence.
And eventually, the rest of Dracula would be reincarnated into Soma Cruz, finishing the redemptive arc. When he passes, all that remains of Dracula will pass from the Earth.
Whether some other Dark Lord takes over the job? That's someone else's game now.