Currently I’m using Joplin with Syncthing-backed file system synchronization. I’m pretty pleased with it, as I do like tagging- and Markdown-based systems.
I plan to upgrade to server-based synchronization, but before doing that, however, I wanted to see what other people are using.
Edit: So far I see a slight favor towards Joplin and Logseq, but I totally didn’t expect (and appreciate) getting so many different answers.
on a desktop or laptop I use Emacs org-mode. on my phone I have tried so many options and the best thing that I found for me is Delta chat. I just use the saved notes which is basically an email to myself.