Metro never runs the TypeScript compiler: Babel 41,624 deletes the annotations, so a file full of type errors still bundles and reloads. Checking is a separate step, npx tsc --noEmit, as the React Native 36,878 docs recommend.
On a phone, a wrong route name surfaces only when someone taps that screen, and in a release build it is a crash that needs a store update. Run tsc in the editor, before commits and in CI.