Many, if not most, mobile devices do NOT support standard “web safe” fonts such as Comic Sans. The will show some alternative font.
There really is no such thing as a mobile specific font. The default mobile font can vary from browser to browser and device to device. Apple devices have different defaults than Android devices. And there is a set of “web safe” fonts that really only apply to desktop browsers. All this is left over from days when mobile devices had limited memory, and so they never really supported “web safe” fonts. In general, for example, Android devices have only supported a Sans font, a Serif font, and a monospace font.
So the only solution to this problem is to use one of the theme supplied Google fonts, or add new Google fonts using the font features of Weaver Xtreme Plus. There are also plugins that can deliver new fonts, especially with the Block editor.
Note: apparently scrambler and I were writing answers at the same time, so there is duplicate information.