I’m just curious, as a male in his young 20s with fulltime job paying 2-3k before cpf. Are there any ways to make use of buying and selling property in singapore to earn big bucks?

Property investing for condo's starts from 500k capital upwards.

HDB BTO will require a spouse, many years of time before you can see your house build up and ready to earn small profit.

Even if there are any other ways it would be tremdemously high risk.

The best investment at 20's is in yourself. Learn a skillset that has an high demand, keep upgrading yourself. Wake up everyday first thing is think about how to earn your first 10k every month or $333.33 per day or $13.88 per hour.

Then come back to learn on advance things on property investing or other means to make your money work for you.

There are no surefire get rich quick schemes. In addition, property investment is now less lucrative than in the past decades ago. For someone young, the best way is to find ways to maximise income (promotion or pay rise) and minimise spending.