Earlier quoted context omitted.
>Do NOT migrate to new tools Completely agree here. For better or worse (well, definitely worse), I've noticed that some part of my brain that loves list-making and re-organizing. This leads me to an impulse to be in a never-ending process of migrating from one tool to another, wind at my back with a new motivated epiphany about how to re-organize everything. Of course, when I say it out loud, it's nonsense, but mome…
If you want to stick with text, I can wholeheartedly recommend Obsidian. It's a bunch of Markdown files on disk and Obsidian does a great job of layering organization features on top of that. (I personally also pay for their Sync service, but you can sync to other devices using other cloud services — they're just Markdown files on disk, after all!)
I guess in truth I have a handful of "requirements" - text based, able to avoid lock-in, able to sync, and cross-platform availability. Looks like it checks all the boxes.