Another option for you if folder management, metadata and search capability are of interest, is DevonThink (DT) on Macs. I use it for organisation, note-taking (you can markup pdfs in DT on iOS/iPad and also all my notes taken in GoodNotes, LiquidText and annotations from Kindle reader get sent to DT and converted to pdf+text files with DT’s OCR which is pretty good).
DevonThink has Smart Folders (ie auto-populating folders that use Boolean-style search queries), fuzzy logic (AI to ‘read’ mis-spellings and typos etc) and you can have replicate files (essentially links to files in multiple folders) or duplicate files (separate copies) as well as index files and content from outside a DT database (ie searchable on DevonThink but stored in other applications or databases). Everything synchs (encrypted) via the cloud (I use DropBox) across desktop and iOS.
How do you do that? Is there a more automatic way than copying and pasting between the notes? I think what I would really want is some easy notation to tell Obsidian to copy this passage into a new or existing note.
I just copy and paste, or transclude. I prefer that, since chances are not all the notes are actually relevant to what I want to write about. Personally, I find the process of curating, reordering, rewriting content/notes/ideas is an important part of the thinking process for me. YMMV
I do wish there were a way to throw a bunch of notes on a workspace, or within a single note, and move them around the way you can with physical index cards. That would be a big game changer for me when writing in Obsidian.