I've gone handwritten, obsidian, onenote, and now Trilium. Considering switching to something else because there is no offline mobile support.
I use memos and trilium together but since neither offers mobile offline support considering switching both. No reason to run two services when I could run one.
As in a folder of text files? Because that's what I'm doing. Syncing across devices with Syncthing and editing/adding files with whatever markdown editor works best in each platform.