You will need to find a RTF to html converter. Convert the RTF to html then display. There are commercial packages (usually for word support). RTF support has wained over the years and most of the libraries will be old. You might want to try (I've never used):
https://github.com/erdomke/RtfPipe
If you envision editing the content with react, then you might want to migrate to a more common format like html or markdown (like the editor on this page).
note: Most of the javascript based editors use html, because the browser has builtin support for editing html.