No, there is no TTF font support in dos-like. There is support for a custom bitmap font format, and you can call `installuserfont` to load one, which returns a font handle that you can pass to settextstyle.
To create one of these custom bitmap fonts, you use these functions in pixelfont.h https://github.com/mattiasgustavsson/dos-like/blob/2b9c90641f81e19f692866601effdaa8ff79b435/source/libs/pixelfont.h#L81-L89
You would loop through all the glyphs of your font, and pass them one by one to the font builder functions, before calling `pixelfont_builder_font` to get some binary data you can save for loading with `installuserfont`.
It is possible to use a TTF lib like stb_truetype.h to render TTF glyphs and pass them to pixelfont builder, an example (and a good starting point if you want to do it) is this code from a different project https://github.com/mattiasgustavsson/yarnspin/blob/79fd13cab1c5d0df2c2fae98d137edfd553223b5/source/gfxconv.h#L264