Both languages are great in performance in RAGE:MP and they're getting better with their response time by every RAGE:MP update. By your knowledge/experience in any of the languages, you can reach the best performance with it. It's depends mostly on how you code/organize your game-mode. So just go with the one that you feel adapting the most. I would recommend Javascript because it's a simple syntax language and easy to understand/adapt fast. If you're into OOP and like Javascript syntax, you can go with Typescript. But since also you have some basic knowledge with C#, you can give it a kick-off. its not end of the world if you choose one and didnt like it. You always have the opportunity to switch and compare between them. It's all about you at last.