what are the different sections in font menu? How do I simplify/clear out unused fonts?
There are groups of fonts separated by horizontal bars. Each section is organized (sort of) in alphabetical order. The first section (not alphabetical) has 6 fonts in this order: Myriad Pro, Whitney, Helvetica, Arial, Bauhaus, Zilla Slab. The next section has 7 fonts in alphabetical order from Acumin Variable Concept (whatever) through Source Serif Variable. Next section has LOTS of fonts: it begins with Apple Color Emoji, then EmojiOne, then it starts at A with Abadi MT Condensed Extra Bold and goes in order through Z, Zilla Slab Highlight. But then, without another horizontal line, the next font listed is Noto Sans Yi Regular, then Osaka, then a bunch of Japanese fonts (actually not sure what these are—lots of asian characters). There are a few Adobe, Apple and other fonts sprinkled throughout (in roman letters). Then Capitals, Apple Symbols, followed by a bunch of arabic fonts, indian fonts, fonts that display as roman characters buyt that have indian-sounding names (each of these language groups seems to restart in alphabetical order)... Sheesh!
The top group consists of recently used fonts. The next group down includes variable width fonts (a single font that lets you change various attributes like weight or slant). Then the rest of the fonts are ones that are installed on your computer and activated via Adobe Fonts.
It sounds like what you need is to filter the fonts. If you go to the font list in the Control bar or in Properties (but not by going to Type > Fonts), then you can filter by font classification and properties, ones that you have favorited by clicking on the star on the right corresponding to a font, recently added fonts, activated Adobe Fonts, or a combination of those filters.