You do get paid for unused solar, it’s just less than it used to be. The idea is that you’re meant to shift your loads to the day. Even without the additional feed in, 6.6kw only costs 2.5k and pays itself off within 4 years if you’re shifting your loads to the solar peak
Also, it feels like you’ve installed an overly big battery system.
Panels and batteries are subsidised here in Victoria and the panels only costs 2500aud for a 6.6k system. Most people spend 20k on batteries or less