I can certainly help with this, and document the scaling logic at the same time.
Certainly don't drop the font, I think it fits rather well.
First issue should be simple, the next issue will take a longer post:
Have you tried adjusting (underneath theme)
columns_mobile = ???
(higher number is smaller font, lower number is bigger font).
That's the simple way of scaling text on mobile (which has a high DPI screen). Desktop text scaling is more complex, because non integer scaling is not supported by default in adventuron, and if it were, the bitmap fonts would look a blurry mess (believe me, I tried).
There are ways around this, and I'll follow this up, but please try the above setting first, if it's not working, then something is definitely wrong.