That doesn't seem to change the scaling. I also get the following error message: Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway. Setting that throws an error.
I also tried checking ~/.config/RStudio/desktop.ini, and line 3 says view.zoomLevel=1.0 which would imply that it's set to 100% scaling, which obviously isn't the case.
Here's what it looks like right now:
Here's another screenshot to compare how RStudio looks on each display (top is monitor, bottom is laptop screen). The scaling makes it so the smaller and lower resolution laptop screen can fit more lines of code than the larger monitor: