I mean, first the manga started with his perspective and if he's a bit honest that's fine. But now we're from the girl's perspective and things have gotten really sugary sweet. And the straightforwardness of the guy makes him a mega flat character, dialogs should have subtext.
I don't like the MC. He doesn't look like a living person, he just says what he thinks without any subtext. This straightforwardness ruined the plot, as if they should get together and end the manga.
An ending without the demonic/elf waifu, meh.
That he'll be remembered as a human even though he's a mix is also complete nonsense (kind of kills the moral of the story).
What a delirious beginning. Raise a prince, train him in everything - not to use him in politics (at least marry him to strengthen his bond with some vassal), not to send him to the army, but just to kick him out... The political map is basically absent. The plot was written by a brain donor.
https://kakuyomu.jp/works/1177354054917371600
It's adapted from a novella. Checked the chapters ahead - obnoxious protagonist, super closed-minded and self-centered. Girls have to jump on him themselves. The author inflates his ego with the fact that everyone is jealous of him. It's awful.