"The real value in using Zotero is building a searchable, sortable, annotated, and organized database of literature. That's what will really pay off 10 years down the line." (Sebastian Karcher).
Here are examples of how some people use it:
Zotero Better Notes helps you to keep your notes organised. You can create main notes, with parts and sub-parts, and link your notes there. There is a button in the Note Editor and in the built-in PDF reader to add the link directly to the right place. Zotero Better Notes adds an extra workplace to your Zotero that opens in a new tab. Graphical visualisation options are available in the outline tab on the left. You can create customised note templates, export your notes to various tools, and sync them to Markdown notes editor like Obsidian.