I use Joplin with encrypted notes synced over Dropbox. I can use it on all my devices plus it has support for math and mermaid diagrams. I also use a Leuchtturm

I use Joplin with encrypted notes synced over Dropbox. I can use it on all my devices plus it has support for math and mermaid diagrams. I also use a Leuchtturm1917 120g notebook which is perfect for writing and sketching with a fountain pen.