About my British passport and nationality

As a Hong Kong citizen, your British passport should only be a British Overseas Citizen passport. Although the name is a passport, it is essentially just a travel document. You can go to many countries without a visa, but it doesn't mean you have British nationality. 1997 Before Hong Kong's return to China, the British government was worried about the influx of Hong Kong people into Britain, so it issued British Overseas Citizen passports to Hong Kong residents. So, to be precise, you should be a Hong Kong citizen with China nationality, but you have no British nationality.