The two have overlapping places, such as splitting the country and subverting state power; there are also some vague places, such as stealing state secrets, which may also be interpreted as subverting the state, but there are still differences. It now appears that the hong kong version of the national security law is the "Spicy" part, which puts the most "Serious" crimes into the hands of the central government, while less serious crimes are handled by hong kong. This may also be the law enforcement model in the future (that is, the national security law for hong kong is governed by the national security law, and the laws formulated by article 23 are governed by hong kong).
Therefore, according to ghost mannequin effect the decision, hong kong will make every effort to promote the legislation of article 23. Although it is not as hot as the hong kong version of the national security law, due to its wider scope, the constraints on hong kong people have also increased. Hong kong's pro-democracy faction has withstood article 23 legislation for 17 years, and may soon fall.
It is also worth noting that article 3 of the decision also states that "The executive, legislative and judicial organs of the hong kong special administrative region shall, in accordance with relevant laws, regulate the prevention, suppression and punishment of acts endangering national security." this seems to be it is a request for "Cooperation among the three powers" and the cooperation of the court system, which china has always regarded as not very obedient. This may also be the basis for rectifying the legal profession in the future.