So, first of all: you don’t have to revoke your citizenship. Once you’re a citizen of both Canada and this other country, there’s nothing this other country can do to make you go home. You don’t have to inform them that you are no longer a citizen; you can just never go there again (or never go to any country that would extradite you to your home country if that is what you are worried about). If this country is indeed out to get you, why would renouncing your citizenship be enough to prevent them from pursuing you?
But, to answer your question: yes, you can withdraw your PR Card application. The best thing to do would be to call IRCC at 1-888-242-2100 to make sure they haven’t already processed your application and then find out if you have to withdraw in writing. (You could also check your status online.) You can also request a withdraw online.