It will try to sync it as soon as it can. If you immediately close GitJournal, it won't be able to. Otherwise, on each modification it tries to sync. (Configurable) Maybe I can add some background sync.
The common use case to see and search through the notes works.
On Desktop I use Obsidian (although most anything will do) and on mobile I use GitJournal which easily links into an existing git repo.