"...when the two sides of a B2B contract are not balanced"
There has been a judgement on this very topic.
Bates v Post Office Ltd (No 3)  EWHC 606 (QB)
There the judge held that the terms and conditions imposed by the Post Office in their contract appointing a new post-master contained unfair, onerous and unreasonable terms. The PO held that the incoming Post-Master was an equal in a business setting, something the judge, Mr. Justice Fraser, dismissed as completely wrong and that the PO had all the power to impose any conditions it liked on the new Post-Master and had abused that power.
The PO got their head handed to them on a plate and they went on to lose the whole case, as many will remember.
So in England and Wales small businesses have a shield against a powerful potential business partner and it looks like SMEs in Australia are now similarly protected.