I have this exact same problem on version 1.2.5033 running on Windows 10. I had the same issue on an older version on a different computer running Windows 7 so it isn't a version or OS specific issue. The youtube the previous poster made exactly replicates my issue. No one ever resolved theirs so I can't use that thread. I have tried changing the DPI settings but any resolution is temporary. Here is an image with my current RStudio properties - compatibility
This is clearly not just me so can we please find a solution?