
The other projects are shown on iOS but are empty.
Now, only one of the tree projects syncs the notes from macOS to iOS. Then I disabled sync on iPhone (deleting all notes on uninstalling Agenda on iOS), uninstalled Agenda, reinstalled Agenda and re-enabled sync. I suspected a sync problem because the number of notes is large, thus I distributed the imported notes in three projects with about 400/400/500 notes.
Waiting for notes to sync to Agenda on my iPhone and iPad (syncing via iCloud is enabled). Import notes from Apple Notes.app on Agenda on macOS (~1300 notes).