I think people are misinterpreting what you're after. People are thinking you want romance options, not romance theme. Romance options would either be a side-plot or one of the genres you mention, hence the issues. To this regard, though, I'd point out that most games are not going to make romance a central theme, but a non-optional side plot: Final Fantasy IX is a classic example from the 90s or 00s, when romance theme without romance option was pretty popular. There is a love triangle, but the main theme of the game is obviously mortality. The main character of the game isn't even the main protagonist (but to point that out and discuss would be major spoilers which i don't want to post here since it is one of those underappreciated gems).

Unfortunately, games, anymore, have focused a bit more on giving the players more options of their own to choose. I think this is a good thing, but it means that more traditional topics are hard to push into a game where choice is fundamental. You're likely to have to abandon gog for RPGs as a genre.

However, Stardew Valley might be what you're looking for, even though romance is optional, because by virtue of interacting to any significant amount with any of the "bachelor(ette)s" will inevitably result in romance being pushed on you.

Though, I have to ask, why are you torturing yourself? Why not use this to better find out how to not be so alone? Getting meaningful relationships these days is hard, but getting with someone to not feel alone actually seems pretty easy. The latter seems like a pretty good first step, just try not to allow yourself to be too emotional towards early experiments. Tends to make it harder for you to attatch to decent people later on.