I think its more of performance issue. When we are building a React application we have to keep this thing in mind that the more code gets large there are chances of performance getting poor. I think you should probably check your app performance and optimize it. There are couple of ways you can optimize the app performance. I can refer to this article which you can study: https://www.freecodecamp.org/news/react-performance-optimization-techniques/

Also if you want to take chance deploy the app on another platform like AWS. If it works fine there then GCP has something to do with it.