Disclaimer: I am building a startup in this problem space. Does anyone think that social proof could work here? If 15 peers endorse Sally for React Native and those 15 people are likewise found to be credible, could such a network effect be more valuable than a coding test?
I'd consider recommendations from CTOs, former Senior or Principle engineers to be the #1 indication that the person can do what they say they can do. Verify a bit more, but honestly the college level micro-optimization whiteboard-only BS questions are mainly only useful for checking new grads.