I bought social security in Dongguan. Can I get a card in Maoming? Does it matter?

Of course. Having a social security card and social security account in Maoming does not affect Dongguan. If you don't go to work in Dongguan in the future, you can move social security in Dongguan back to Maoming. Social insurance is a kind of welfare given by the state to the people, with a wide range of protection and a relatively low degree of protection. But social insurance is the foundation, commercial insurance is the supplement, and the function of social insurance is irreplaceable by commercial insurance.