I posted about Kano discussing her salary with a baseball player. Kano never played an active role for the team so it's understandable that her pay was lower despite being an Olympic medalist. She was already an inhouse model for Mizuno and Champion by 2016 so she gets a bigger cut from those sponsors. She is now one of the highest paid former volleyball players which was revealed by PR Times.
Another great example would be Ranna Shiraiwa who gets a bigger cut from brands/stores in her area than previously in Forest Kumamoto. None of those brands have any relationship with the club. As for the specifics, I don't know exactly how much she earns from those.
Nagaoka is also doing side jobs under Bon Image Corp.