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.
The first point probably comes down to time. When they designed the phone, RAM was more expensive and phones came with 1-2-4 gigs.
The second one is manufacturing cost. If they could sell at least a few million units, it would be way cheaper.