I'm not quite sure what about e.g. Roboto or SF Pro Text isn't suited to long prose, or if you think OSes ship with just the font used for system UI (and not al

I'm not quite sure what about e.g. Roboto or SF Pro Text isn't suited to long prose, or if you think OSes ship with just the font used for system UI (and not also dozens of others several of which were pretty much designed for longform text).