I've had this issue with LGM on my high DPI 2K monitor for a while now. I even have the issue running LGM under Java 9. I finally did some research and found a workaround I'd like to share.https://superuser.com/a/1207925
I tried that on my installed "javalocation/bin/java.exe" but it didn't work at first. So what I did was ask the MSYS2 console where java is.
$ where java
I then went there and applied the fix to that exe and it worked. You just right click the exe->Compatibility tab->"Change high DPI settings" and override the DPI scaling factor. I set mine to "System (Enhanced)" to get the results below.
DPI System (Enhanced)