Looking to start keeping some daily notes. I don’t mind paying for the app, as long as it’s one time and not subscription. Bonus points it it on f-Droid.
I use Obsidian.md, which starts as a note-taking app, but can end up as a whole knowlegde base. It has a built in core plugin for daily notes, but the plugin ecosphere will allow you to go way beyond that. It is free, however the built-in syncing is a subscription. You can just set up and use any sync service you want, it even has approved plugins for that, as the subscription is basically just a donation.
There is an open-source alternative called logseq, available on fdroid, i dipped my toes into that one for a while, but the plugins on obsidian like dataview and templater are just invaluable.
I use Joplin for notes, though if you want daily notes specifically “Diary” might also be a good choice.
Joplin is great for notes. I’ve set it to sync with a free Dropbox account and have used it on Android, iOS, Linux and Windows.