RStudio already works with Apple Silicon, and can bind to the native Apple Silicon builds of R for macOS; the essential components of RStudio (the ones that connect to R) have already been ported.
However, the front end isn't native due to a 3rd party component dependency; it still runs on Rosetta2. You can follow progress on that front here: https://github.com/rstudio/rstudio/issues/8652