Is it permissible to create a charitable application with a symbolic monthly subscription that includes a draw for monetary prizes for subscribers, with the rest of the funds allocated to charitable works?

What you intend to do is a form of prohibited gambling, because the participant pays money hoping to win a draw. Gambling is any transaction in which a person oscillates between gaining and losing, and it is among the major sins. The assumption of donation here is far-fetched as long as the payers are entering a draw. However, if a donation channel were opened for the wealthy, and the draw was restricted to the poor who do not pay a subscription, or if money was collected and given monthly to one of the poor without a draw, then there would be no harm. Gambling is an abomination of Satan's handiwork, and Allah has associated it with intoxicants, idols, and divining arrows.