I've had a positive experience participating in ApartResearch.com research sprints. I was able to win (with my team) 4th place on the Defense Acceleration hackathon and then most recently on the Technical Governance Challenge, we won 1st place. I know they previously hosted some on Biological Xrisk for AI, which might be something you're interested in.

From these experiences, we actually got the opportunity to interview for fellowship positions, which we are considering. I think given your PhD in a hard science, you could link up with people that are interested in similar research as you are and then from there figure out where you want to publish.