I went through a bunch of the google translated versions of the WN, so I can confirm they do have a semi-romantic relationship. I say semi because I have yet to see them openly admit the romance despite having a few lovey-dubby scenes together.
This is clearly a prequel to Shikkaku Mon No Saikyou Kenja
https://mangadex.org/title/21901/shikkaku-mon-no-saikyou-kenja-sekai-saikyou-no-kenja-ga-sara-ni-tsuyokunaru-tame-ni-tensei-shimashita
Read what was already translated on Novel Updates and the story is quite good. I agree that it isn't really a comedy, but they do have some humorous moments with how contradictory their evil nature is.
It is refreshing to see an iskeki with a rational protagonist at the start.
Imagine being kidnapped by a foreign nation and then being told a fairytale encouraging you to fight blindly against another nation you know nothing about. Anyone with a brain would go fk no, I'm out.
There is a lot of pointless fighting going through up to chapter 31 in the raws before I gave up skimming through them. I didn't see any NTR or rape but the attempted act was stopped by a passerby.