I work pretty extensively with Google Apps Script in my role at work, and was really happy to have discovered Google’s clasp utility: https://developers.google.com/apps-script/guides/clasp
In short, it lets you pull all your Apps Script code to your local computer, use an IDE like Visual Studio Code to work on it, and push changes back to the Apps Script project.
Even more, clasp lets you use TypeScript to write your Apps Script code, giving you access to ES6 features if you go that route: https://developers.google.com/apps-script/guides/typescript
I thought some of you might find this helpful to learn about.