1000 times asked here (and also answered
- you could have used the "SearchBox" in the right above corner).
Anyway to make it short: the base game isn´t this big (less 20GB extracted), the main functions of the game didn´t change significantly within the last years.
But most of the size are the tons of mods created by skilled creators (skins, hairs, body parts, makeup, clothings, accessories - all for creating beautier and more realistic characters to play with or using them in StudioNEO) .
And there isn´t a compression system in this game (as in AAA games is usual) - especially the textures are mostly big files.
And the 192GB is the "Optional Sideloader Modpack Studio" - as the name tells you it is a modpack ONLY for StudioNEO and NOT for the game - you don´t need this unless you intend to intensively work with Studio (creating your own scenes and animations).