a less warm couple. not many smiles in general unless it was reigen's sleazy small open-mouthed grin. although you sometimes got artists who portrayed them warmer, it's not the same as anime mob and reigen fujo content.
the affection was there, and obviously with fujo art you're gonna have a more affectionate pair compared to canon, but considering the medium they're basing the content from where facial expressions and composition carry more weight, reigen and mob aren't going to be as animated in attitude like how people usually reference from the anime.
thus having reigen's expression involve lowered eyebrows, having a generally distant and neutral face, lack of elaborate hand movements + mob already being mostly expressionless made for a pair that seemed to function based on subtler affections and non-extravagant actions.