Everything depends on your experience, but in my opinion, companies that would only hire based on tech stack aren't worth working for anyway. And marketing yourself on your stack is a bad idea. Ask yourself, what kind of problems are you able to solve? Which domain do you know? When you find the answer, sell that. If you know really well how to solve some issues, you can solve them in any language. And you're not paid for the code you produce, but for the problems your code solves.