I adore sisterly love between the two and wish there was more of it both in art and in canon.
Zipp feels like the kind of person who rarely really lets her guard down anyway, and that her sister is one of the only if not, the only one she ever fully lets it down around.
I know the tags are showing shipping, and it’s pretty cute that way, but I think this could also be seen as family love too. I like how Zipp’s ‘Love you too’ is slightly greyed out as if she’s embarrassed saying it.