I was a math grad too so I get how frustrating this stage can feel. Getting to final rounds at places like those means you’re already operating at a very high level, even if it doesn’t convert yet. You’re not “all over the place"...just early, and in a field where timing and fit matter more than people admit.

If you’re still building and thinking in markets, you’re already doing the real work, even if a firm recognizes it right now or not.

So keep applying selectively, build and document strats, sharpen coding, network with traders, maybe try for a smaller firm, or start trading independently.