Yeah, Makoto is in pretty deep and is pretty staid in her ways to boot. Sure, things could go south but generally she's presented as one that keeps, from her dad's moisturizer, to her ideals, to her pencil case, to you.
Plus it is damn obvious from the date scenes (and the conversation about her dad and his passion) that she feels more than she lets on explicitly.
Her relationship is about finding a partner as much as it is about finding someone to open herself and the world up to her.
Her looking for a "study partner" is her being coy and embarassed and unexpressive and trying to avoid the issue. Just as when she sneaks your number and signs you up as her fake boyfriend without your say-so. She's trying not to broach the issue while also trying to push something to happen. And she is always embarassed/sheepish about it after the fact (which is how she feels about her passions). It isn't literally an experiment where she's taking volunteers.
...
But it is an interesting issue...
I dated Rise in P4 and that is a relationship I saw falling through eventually after she returned to being an idol. Both because a boyfriend is explicitly what she was looking for and because an idol career is not kind to relationships.
The way I saw it, Rise was (at first) into MC as eligible, generic boyfriend she wanted to have. She became an idol because she wanted to reach out to people and found it lacking. She stopped being an idol again to reach out to people and have a certain experience she wanted, which included a boyfriend. Couple that with a desire to "work her wiles" and there is a certain falseness to her approach and the MC sort of thwarts this falseness in a mix of getting her to open up as a person and not falling for a lot of her ploys. This both confuses and frustrates her and makes her actually come around to loving the dude, but I imagine dating her would very much be the "high school dating experience" and you'd never really break through all her issues and that it is telling she comes around to idoling again, as if she had accomplished what she'd set out to do with you already.