^ JunNana are interesting because they have a dynamic that instantly fits together and is arguably the most domestic in the show- they're not as competitive as MayaKuro, not as naïve as KareHika and not as mature as FutaKao. I call them newlyweds because they're at the arguable peak of their relationship- they've been together for long enough to fall in love with each other, clashed a few times over minor issues (like the Class Rep position), and know exactly what to say in order to support each other. There's no need to dramatically prove their love, and no need to renew it- it's incredibly stable, even within the revues, without the greenness or the rot.
Of course, this is all from Junna's perspective- in Nana's eyes, their relationship is essentially a chemical formula that's painstakingly recreated year over year, with everything measured out and maintained, isolated from new elements. It's a flower in an artificial greenhouse that feeds off itself, blooming without ever creating something new. The newlywed metaphor still works, because Nana is striving to keep them in that ideal space.
Your point about Homura is quite pertinent, because I think Starlight is what you'd call a post-Madoka show, made at a time when brutal deconstructions of optimistic narratives were quite popular. While it's more inspired by Utena in terms of aesthetics, the time-looping and the deal-offering giraffe were anime-original elements specifically meant to evoke Madoka. Nana is quite similar to Homura, Hikari wants to be both Homura and Madoka, and Karen hilariously just goes, "Guys, this isn't Madoka. Can y'all stop being so edgy?". It's basically what you'd get in a universe where Madoka as a show was super-popular and became adapted and imitated across every form of media, butchering and time-looping countless lesbians for tragedy, until a bunch of girls in 2018 took a look at the script and went, "Well, this is nice, but don't you think it's a bit too melodramatic, contrived and edgy for our time? Screw this, let's show all those edgy audiences that a happy ending can be simultaneously more intelligent and more entertaining than a bury-your-gays tragedy." And boy, did it work magnificently.
Also a rather long comment, but I will gush about Starlight till the end of time because it's a masterpiece.