Kronii was interested in Vesper, whether it was just for friendship or for romance is up for debate, but you can't deny she was going for him. Kronies got lucky that Vesper turned out to be a manchild who would fight with management and ghost people when he doesn't get what he wants. Here's the stuff that Kronii did that were unique or unusual for her:
>Kronii got management involved to make a statement to back up her decision, which is the first for HoloEN
>Kronii did a 1 on 1 collab with Vesper that she's not done for any of the other homos
>Kronii who rarely if ever joins in on other people's streams unless she gives a heads up beforehand, easily joined the Tempus RP collab to play as Axel with no notice
>Kronii who usually will take weeks or even months to collab with someone she recently has a collab with unless its some sponsorship/mandated stream, was able to easily include a collab that has Vesper
>Kronii who is usually reserved and chill, so easily laughs or assertive when its in a collab with him
>Kronii admonishes people for shipping her with Altare but doesn't say anything about people shipping her with Vesper
>Kronii expressed wanting to make new friends but hasn't made any effort to even acknowledge Tempus 2, especially Flayon which she could have done a VA collab
If he didn't fuck up so badly they would have been pretty close and easily could have turned into a unit. You can look up the archives of /infinity/ to see the kind of activity Kronii had months prior to Tempus and see how she drastically changed after the first collab with them.