Hey stmn, idk whether you will update this tool, but I at my ct.js game engine have a solution for font blurriness.
The easy way is rendering the font’s canvas at, say, x4 size and downscaling it by drawing onto another canvas while disabling image smoothing. (MDN docs.) You can also access ImageData and threshold the alpha-channel to remove the remaining blur.
The hard way (that I use in ct.js) is parsing the font file with Opentype.js and drawing the symbols as paths. This eliminates the symbol blurriness problem, but has another issue with 1px-wide lines as they get broken, so I firstly draw everything at x2 size and then downscale it. The results are then perfect and don’t require further filtering.