The biggest near-term threat is probably bioterrorism. You can get arbitrary DNA sequences synthesized and delivered by mail, right now, for about $1 per base pair. You'll be stopped if you try to order some known dangerous viral genome, but it's much harder to tell the difference between a novel synthetic virus that kills people and one with legitimate research applications.

This is already an uncomfortably risky situation, but fortunately virology experts seem to be mostly uninterested in killing people. Give everyone with an internet connection access to a GPT-N model that can teach a layman how to engineer a virus, and things get very dangerous very fast.