Increase R memory allocation in RStudio

Hi Rstudio Community,
Similar to this post and this post, I'm trying to allocate more RAM to R4.3.1 [64bit] using RStudio 2023.06.1 Build 524. I'm running these in Windows 11 environment with 64GB of RAM but cannot get R to use more than 3GB (see screenshot below). I double checked and my global option settings for R is set to the 64bit version i.e. [64-bit] C:\Program Files\R\R-4.3.1. I would appreciate any advice. Thank you