If your existing large app is a React app, the naive thing to try would be migrating the src/ folder into a new CRA app and see what happens. If you get a lot

If your existing large app is a React app, the naive thing to try would be migrating the src/ folder into a new CRA app and see what happens. If you get a lot off runtime errors you have an easier time migrating to CRA, if you eject a new CRA app and gently/iteratively adjust the webpack config on your existing project to match CRAs.