Yes, rewriting is always an option, I've done it personally many times. However, re-writing a bigger application to plain JavaScript can be very time consuming because you would need to take care of functionalities otherwise handled by React. In other words, React (or other framework) can save a lot of time providing the core functions.
It very good approach to not give up, React is not that difficult to learn as it may seem. Some time ago I learned it on a course, PM me for details if you want. Otherwise,
this is the place to start. Video showing its usage and integrating Bryntum Scheduler:
- clean-react.gif (18.44 MiB) Viewed 2774 times
Wrappers are actually thin layers between Bryntum Scheduler which is written in vanilla JavaScript (without any framework) and React. In other words, wrapper "converts" scheduler to a React component so that it can be used the same way as other React components.
More information here.
Yes, React can be used to write an enterprise-grade app. Create React App scripts are very helpful. They allow you to run a development server while writing the app and then to build a production version of the app.
Summary, I probably wouldn't go without a framework but I'd choose some of them. React would be a good choice.