Recent ones I’ve been trying on Linux:

• Logseq (Markdown only)

• Flatnotes (Markdown & WYSIWYG)

• MarkItUp (Markdown & WYSIWYG)

• Trilium (Markdown & WYSIWYG)

By far, I’m enjoying Trilium over the others. Trilium can do LaTeX, while Flatnotes and MarkItUp can’t (don’t remember if Logseq can). That coupled with What You See Is What You Get (WYSIWYG) note taking - the kind of text editing like Microsoft Word, Apple Pages, or Google Docs - makes thing work just like OneNote. Plus, one of the things I was really looking forward to seeing in a Personal Knowledge Management System (PKMS) was a graphical/node map view of all my notes, which again Trilium does.

I’m actually considering making one of my old laptops a perma-server that I can run Trilium on so I can access it on both my new laptop, my phone, or pretty much any other device with an Internet connection.

Last thing I’ll say is that it doesn’t hurt to try everything and see what sticks!!! Before settling down on something permanent that works for you, that is.