NGL, I don't think it's the king that has mandated that the "hero" be banished to eternal community service. While true there are many reasons the rulers of a nation wouldn't want the first generation hero to stick around after achieving their mission, here there is mention of religious mandates and divine dacrees. It honestly sounds like the gods f-ed something up, and are trying to course correct with this magical book of relationship quests.
Something about the world building feels juvenile. Not in a bad way, but like the god is unexperienced and running on tropes.
A standard fantasy setting. Good boy human hero who does good things all the time. A demon lord threat. Modern Otaku tropes and memes that aren't applied quite right in a subculture that has anachronistic merch.
And then this hamfisted, if adorable, course correction by a book that is doing its damndest to paint by numbers into a different genre of manga.
It feels like somebody got isekai'd as God, didn't like how things played out with their first draft but couldn't start over so they're just trying to change genres.