How do you manage the funds intended for downpayment of private property?

When you say you're risk loving, you probably mean you're high reward loving. At times, high risk do not equates to high reward.

If you're worried about not being able to pull out the money in time, your risk appetite might not be as high as you think. To me 4 years is a medium term horizon, investing in stocks with good fundamentals is ideal. Plan your risk management and cash allocation properly.

If you have spare cash, invest in growth stocks since you're still young and have a longer time frame.

You can invest in US stocks directly via international brokerages, or invest in ETFs with US exposure.

Do approach a conflict-of-interest-free financial adviser for further advise if you need.