Have you considered booking a call with 8000 hours career advising? They can help you analyse the factors behind your plans about your future career, and put you in contact with people working in the areas that interest you.
You could also contact CLR and CRS. If you show knowledge of and interest in their work, they may be eager to help. You can’t be sure if you’ll get a reply, and that may seem intimidating, but remember that the cost is minimal, EV is high, and how you feel about not getting a reply is at least partly under your control.
While this last point is not specifically focused on s-risks, a very cheap, very valuable, action you can take is subscribing to the AI Safety opportunities update emails at AI Safety Training. Many hackathons advertised there are beginner-friendly.