I have installed the following versions of R using rig on my Macbook M1.

❯ rig list
* name       version    aliases
------------------------------------------
  4.1-arm64  (R 4.1.3)  
  4.2-arm64  (R 4.2.3)  
* 4.3-arm64  (R 4.3.2)  release
  4.4-arm64  (R 4.4.0)  devel

When I set the default version using rig default, rig rstudio launches RStudio with the default R version (here, release). However, if I specify a non-default version (e.g., rig rstudio 4.1-arm64), RStudio still launches with the default version instead of the specified non-default one.

Moreover (but maybe unrelated), if I specify the version number instead of the name (e.g., 4.1.3 instead of 4.1-arm64), I get an error message: [ERROR] R version 4.1.3 is not installed.