LCDs on these small systems are general pretty low resolution and would greatly benefit from subpixel font rendering. The normal way to do that is to triple the horizontal resolution of the font bit map. That works out to 3, 6, 9 or so bit per pixel. Freetype can generate these horizontally expanded bitmaps. I suspect the online bitmap font generation tool is freetype based?
For example the letter ‘l’
RGB RGB - two pixels on display
001 110 - single bit
013 310 - two bit
027 720 - three bit
These horizontally expanded bitmaps compress down a lot. But the decompression and compositing code needs to be aware of the triple horizontal expansion when mapping to 16b or 32b final pixel colors.
This does not have to consume a lot of ram. It may work out that a 6b per pixel font looks better than 8b antialiasing. Note that you can even subpixel render the character width and kerning if you wish.
I noticed this issue when running the demo that prints the blue button with Hello World. The parallel 'l’s have color fringing and turned bluish. I believe subpixel rendering can turn them white.