Just curious about this, since there’s a lot of people (including me) who jumped around Evernote, Notion, etc.
But I know that there are also people who were full-on using markdown for years.
Was wondering what kind of app/system you guys used to make this sustainable. Especially if with sync to Android or iOS!
I recently learned about org-mode too, and people seem to have made a lot of stuff with that.
Tools: Onedive - Typora - TickTick, with a deep folder structure 
Find Notes: Windows Search and/or Everything Tool
Filenames: Clear filename with keywords/tags - for quick search
Now I use obsidian and not so much has changed.
I mainly use it as a personal Wiki
About mobile
I used Simplenote on Windows/Android/Linux. I’ve been using it for the past few years but have found it cumbersome with how I’ve been approaching work at this job I’ve recently moved into (IT).
I’m still using Simplenote lightly for quick notes/scratch pad type of stuff and then I’ll eventually (or that’s the plan) move it over to Obsidian for better searching/linking (the key draw factor for me).
Notational Velocity → N/V Alt → Simplenote ->Obsidian
+Apple Notes (will move to Obsidian once I figure out how)
+Drafts (quick text jotting prior to move elsewhere)
+Yojimbo (my reference library and archived websites)
Evernote (for years) => Zoho Notebook (for years) => HTML export converted to Markdown with Pandoc, and now Obsidian/Sublime Text/Typora/1Writer/Editorial/DrWrite with Dropbox syncing.
https://ryanpcmcquen.org/DrWrite/
I love the portability/flexibility/longevity of plain text. Both Zoho and Evernote had handwriting OCR, which is really neat, but Dropbox is adding that, so it’s not a big loss and the pros are higher than the cons at this point.
Evernote for web clipping and black hole capture (i.e, i saved a lot of stuff, rarely accessed). For markdown notes - nvAlt
TiddlyWiki. I still love it but… there are times when you just need to go on…