21f need help investing family wealth

Hi, would like some advice on how we can diversify and invest around $20m AUD ≈ 13.5M USD of liquid cash.

Long story short, come from a well off family in Australia, but dad has always just invested into real estate cuz that’s how he started and all he ever knew. Has a multi 8 figure net worth but mostly in just real estate. Only 1m invested in a managed fund from 15 years ago. Currently have 20m in just cash just sitting in term deposits that we’re looking to invest elsewhere but we don’t know where or who to trust?

We’ve talked to a lot of financial advisors but they all end up just recommending their own products. The other high net worth individuals we know just do real estate aswell, but as we’re currently doing more real estate projects it just gets stressful and more risky and returns are not always worth the effort. We know there are other ways such as index funds etc but don’t really know how to work with someone we can fully trust. No one in our family works in finance either.

Any recommendations on how to go about it?

also note: we don’t do negative gearing all real estate investments is paid in cash