I also have a non-union fracture that I will be having surgically removed along with an os trigonum. My doctor is also recommending that I have ligament repair for my instabililty. Dear Kristina, Without more information, it will be difficult to answer your question. However, I will try to make some recommendations. The chronic ankle instability you describe should not go unaddressed, particularly in your field.
Many dancers have successful careers after surgical ligamentous repair.
Others continue to dance without surgical intervention, opting for extensive strengthening programs and taping techniques for added stability. You also mentioned having an os trigonum removed. If you will have surgery for your fracture and removal of your extra bone - you may well consider ligamentous stabilization at that time. This is a conversation that you should have with your surgeon. Ultimately, the decision is yours.