In the Editor mode they currently support collapsible headings. Yet not so feature-rich yet, e.g. without collapse all or open all.
Besides, I came from Dynalist, have been using Roam and Notion and now discovering Obsidian. Sometimes I switch tools quite often, although everything is evolving.
Yes, outliners are different from note taking apps.
Outliners fit my speed of thought, quick rearranging of ideas and mixing content. Note taking apps like Notion and Obsidian requires some more structure from yourself I feel.