A bit OT, but I have a client from HK whose parents were born and raised in the city but were also British citizens. Since he himself was born in England he's also a British citizen with a bona fide British passport, not the BNO kind.
His business is in Mainland China so he travels between the Mainland and HK all the time. He's a permanent HK resident with a HK ID card and passport that specify he has permanent right of abode (HK doesn't have 'citizenship' per se).
He holds an entry permit card that allows him to travel to China unimpeded and visa-free. He can work and live in any Chinese city as if he's Chinese national, pay his taxes there and is subject to Chinese laws.
He's never been required to present his British passport whenever he enters China from abroad, nor does he need to. All that requires is his HK passport and entry card, and immigration just waves him in.