All Garmin has to do is to put the fonts into the watch and no more blocks but for some odd reason they won't do it
Unicode glyph management in embedded systems is actually a non-trivial problem. There's a lot of potential glyphs and not only a small amount of RAM to cache them in, there's significant resource hit to pull uncached glyphs out of slow storage.
I do not know the details of Garmin watch memory infrastructure, but in many embedded systems every piece of (let's call it) "always accessible" RAM is full, and there's a developers wishlist of things they could put in it. However increasing the size of "always accessible" RAM is a power drain.