It might be worth asking yourself where you want to be in your life right now. One thing that stands out is you and your girlfriend both have the right to work and stay in Hong Kong - this makes it easier for you both as you don’t need to rush into marriage at your age. Life is actually full of ups and downs. Many circumstances change and so do people from their mid 20’s to mid 30’s. With uncertainty in immigration and the overall job market, jumping into another long term commitment, marriage, further restricts your options to adapt to changes as they emerge in the next couple of years or more.
If having a property is a condition to marry, you should think are about what this means. Do you need to burden your family for assistance? Do you need to burden yourself at your age with commitment? You are in a tough place and based on people my age and myself, it’s probably better you make the simplest decision right now for yourself. So many people hold deep resentment after giving in to unreasonable demands. If you feel you are not ready, don’t do it.
The right to reside in a country and property are the two biggest obstacles that most people face. And this is even a challenge for those a fair bit older than you.