I guess that my main problem right now is that we don't know anything from Riko, I'm not saying that she can't be allowed to be that much of an angel, but the only thing we know for certain is that she is a sex worker and kinda looks like she already fell in love. For Momo, sure, it's easy to get in love through sex, but Riko is supposed to be experienced so her looking like she already fell for Momo is what makes it weird.
Then again, most of this stories come in one-shots so it could be me bitching about this taking too much time to develop kek.
Also, agreed with that last part but tbh, having an active social life id more important than looks for that. (So yes I'm kinda saying that shy but good looking people can struggle to get laid kek)