I reckon HK has a low probability of gaining their independence from China. China is too heavily armed and too willing to effect total genocide for HK to have a reasonable expectation of prevailing. I note that Texas was in similar straits once, vis a vis Mexico and Texans fought anyway, taking a stand in an old mission church called the Alamo.
Everyone died in the battle with Mexican troops led by Gen. Santa Anna inside the Alamo. Later, Texans remembered the Alamo, and today Texas is no longer Mexican territory. 'Remember the Alamo!' remains relevant to Texans today.
If Hong Kong falls, every free man, woman, and child in the world will remember Hong Kong and the stand they took to defend their freedom from utterly obscene totalitarianism and Chinese crimes against humanity.
Mexico survives today. They only killed a church full of men. If China takes Hong Kong, they will destroy an entire nation, likely killing or enslaving every single person in HK to do it. The world will remember Hong Kong, and I doubt China will survive that memory long enough to pass regret for that genocide down to their children.
Remember the Alamo! Long live Hong Kong!