I haven't really read anything of Arioto beyond what was adapted in the manga, but I think the only thing they really have in common is the power exchange dynamic they have going on. Even then though, those dynamics play out very differently. In Arioto, the exchange is mainly an excuse for Mari to explore homosexuality without feeling ashamed. In ShuuKura, the 5000yen makes their relationship transactional, which frees them from typical social inhibitions and gives them a space to be their authentic selves and cultivate a real connection with each other, something neither of them have really had before. Sure, Miyagi has Maika, but there's clearly boundaries in their friendship that don't exist with Sendai. Miyagi likes and trusts Maika, but you can tell she's never truly been emotionally vulnerable with her and doesn't want to be.
I'd also say Arioto is more interested in exploring things like queer identity and community, and learning to embrace that and overcome internalized homophobia. I have yet to see any character talk about their sexuality in ShuuKura, even internally to themselves, which I guess is pretty common for yuri. Most works seem to intentionally avoid putting LGBTQ identity labels on their characters. ShuuKura is exclusively focused on the relationship between Miyagi and Sendai and the personal hangups that prevent them from actualizing their relationship into something permanent and truly intimate.