Setting LCD gamma / contrast (IntelliJ IDEA, JDK 8)
You said that the normal openJDK works the way you want him to work, correct?
If true, Why don't you change the JDK IntelliJ use?
I believe it is platform SDK in preferences.
FWIW, although zooming into the current rendering (IC 2020.3) looks similar to the original screenshot:
I no longer feel this looks too bold or blurry. Perhaps it's the slight change of font (using JetBrains Mono now).