I know this is an old topic but I think there is a better solution for the font scaling. The problem is that for a lot of monitors, you want to scale up by a fraction, for example 1.5 seems to work well for mine. The solution above only allows for an integral scaling factor.
You should edit Defold/config and find the vmargs line. Change it as follows:
vmargs = -Dglass.gtk.uiScale=1.5,-Dfile.encoding=UTF-8…
If you don’t want to scale by 1.5, include your own value of course.
Perhaps this could be added to the Linux FAQ too?