Thanks a lot for your answer! I really had no ideia that it was limited per IP/Client ID, I thought that I had only 30 calls per ID, so if that really works like that the 30 requests are more than enough and i need no auth.
I am going to do a backend and cache system in the future, but for now, I want to release the application as soon as possible and after that I have more time to learn some backend framework like node/express/next to add more features to the app (like user actions with auth). I only worked with Java and Spring so far, it is the first time im using javascript frameworks.