Javascript – React doesn't show changes

When I create a new react project like this:

npx create-react-app my-app
cd ./my-app
npm uninstall react react-dom
npm install react@18 react-dom@18
npm install web-vitals
npm start

The loading is really slow.

also when i edit /src/app.js and changed the text there(for example, added <p>hey</p> to the default project) I don’t see the changes when I refresh the browser(tried to change browsers and be in incognito).

I work on WSL but the project is in C drive.

For example:
I run without lines 7,13.
The added them and made refresh and don’t see the changes in the tab.