She wants me to sign away rights so that her new husband can adopt him so they can be a family. But she is unwilling to drop the support order so I don't feel she's genuine about this. We also live a few states apart. What can I do since I can't afford a lawyer and she gets a legal aid one

If you owe any back child support, you will still owe it,
Once the adoption is done, any current child support will stop.

She has no real choice about that. So tell her that current payment always stops when the adoption is final.

If you agree to the adoption your support obligation ends when the adoption becomes final. She has no choice in that. However, you may still owe any arrears that existed at that time.

Thank you