Your result
Australia — Marriage
Not eligible
A person can sponsor a partner for an Australian visa twice in their lifetime, and on what you have described your partner has used both. That closes the partner visa route through them, and it does not reopen with time in the way the five-year rule does.
There is one way past it, and it is discretionary. The limitation can be waived where there are compelling circumstances, and the cases that succeed tend to involve something that makes the limit produce an obviously unjust outcome — children of the current relationship, the death of a previous partner, or previous relationships that ended through no fault of your partner's. It is worth putting in front of someone who can assess the actual history rather than treating the limit as the final word, because the threshold is about the circumstances rather than the number.
If no waiver is available, the route into Australia has to come from your side rather than your partner's. Points-tested skilled migration and employer sponsorship are assessed on occupation, age, English and work experience and are unaffected by your partner's sponsorship history. If you qualify on those terms, your partner's status in Australia becomes an advantage in the application rather than the basis of it.