(Only .otfs were installed)
Hardly readable

You can stop using Bold font in your syntax theme then
.otf plays really weird on IntelliJ products (maybe because of Oracle's Java, Azul & Open JDK has better rendering) use .ttf instead for better rendering
Just in case someone stumbles upon this - I am encountering this on Windows - here's what I did to finally get the same font weight as I do under Linux.
Just extract all the ttf files to your installation's jre/fonts subdirectory, e.g. C:\Program Files\JetBrains\IntelliJ IDEA 181.3494.3\jre64\lib\fonts
Most helpful comment
.otf plays really weird on IntelliJ products (maybe because of Oracle's Java, Azul & Open JDK has better rendering) use .ttf instead for better rendering