How to update Quarto version installed with Rstudio

This won't.

The quarto you are actually using is shipped with RStudio IDE. If none is found installed, it will be using that one.

If you install a new one, RStudio IDE should find it, and use the new one. There will be no conflict. quarto is a standalone binary, and the one shipped with RStudio IDE is a portable version.

Did you try it already ?