Bocchi is incredibly gay but Kita and Nijika simply have more experience. And Ryo hasn't been practising so she only has her natural lesbianism to work with... which is still a lot but lower than the rest of the band.
@Ferhog I think this art at the very least is meant to be super gay, in theory anyhow. Since it's not just two bride outfits, Ange is dressed as a groom and Charlotte is the bride being princess carried, they're also looking at each other and not the viewer.