(not op) Logseq is open source and really great in the way it connects notes and highlights pdfs, but the sync part is too “asynchronous”. It works well if you use a single device, but as long as you add something else you have to manually reindex and refresh a lot.
Obsidian is less opinionated on the txt file format and folders too, so I consider it more future-proof.
I started with logseq and now obsidian doesn't work for me anymore. Tried to switch but I am into this small self containing bits now.
Plus journal with timestamps
Syncthing is very good, but the best iOS implementation, Möbius Sync[1], is not comparable with the Android one (the OS limits the syncs, you need a regular notification and so on).
The great things about Logseq are his weakness for me. Everything is so interconnected (you can say: "here put the paragraph of this other note") that I sometimes lose confidence in the system. It becomes too complex. With Obsidian I know that a note is a file. Less convenient but simple and reliable.
Logseq really excels with his outlining mode, I miss it (but I don't like the way it saves states in the markdown file). It has some problems with the code blocks too.
Can you elaborate on the syncing part? Last I tried Logseq, syncing across devices via iCloud was very unreliable. So I gave up. Although I would have loved to replace Roam with Logseq back then. Now I stick to Emacs + orgmode and Obsidian for plain markdown files.
I have a folder in syncthing called "logseq". This folder holds the logseq files.
I have logseq-sync on my phone so it syncs the folder. I also have a Cloudserver which is the spoke and all other devices (2 laptops, the phone) sync it.
Obsidian is less opinionated on the txt file format and folders too, so I consider it more future-proof.