Personally I've never liked how tools like Remix or NextJS have mapped a nested file system to routes. Simple things like "I want to put this component in its own file" become annoying tasks.
I've always been a fan of "flatter" file systems, my files often look like this:
/App/
TypeScript has support for type-checking plain JavaScript files, which is very useful if you have an existing JS codebase and you want to test the waters and gradually add types.
There are some limitations in what you can do in JSDoc, but a lot of them can be worked-around by using type-definition files .d.ts (for example in a types/ directory). These files don't generate any JavaScript code, they are just there to provide extra type definitions to the compiler.
One thing you can't do in those .d.ts files though, is use enums. You could define them of course, but you won't get the runtime representation since the files don't generate JS code.