Why does my React Native app build successfully despite TypeScript compiler error?

I've recently started using TypeScript with Expo. I've done all the linter/formatter integrations like typescript-eslint so I can catch most of the errors during coding. To check if the code compiles, I run npx tsc every once in a while and fix accordingly.

One thing that I haven't fully grasped yet is why my app builds successfully even when there are numerous compile errors. I expect (and prefer) to see a red screen error for every compile error rather than the app build successfully and me find it out later. For example,

function square<T>(x: T): T {
  console.log(x.length); // error TS2339: Property 'length' does not exist on type 'T'.
  return x * x;
}

is a typical TypeScript error that (I believe?) can be easily checked at compile time. I want it to result in a big red screen error and the build to fail.

I'm quite new to TypeScript so it's possible that I'm missing something very important. What exactly is causing this leniency and is there a way to enforce stricter checks?