Synchronization intervals / process

Dear community,

I’m pretty new to Nextcloud and I’m thrilled by both the privacy implications as well as the possibilities. Thrilled enough to build a whole Ansible playbook for setting up my nc instance but anyway.

I’m using it to synchronize my documents, including my password database (plain encrypted file), and I’d like to keep these important files as synchronized as possible.

While using ownCloud on my business Mac, I noticed that any changes I make locally are pushed to my company’s ownCloud in an instant. As far as I understood, the Nextcloud client is the ownCloud client with a different branding (on some platforms?).
However, if I’m running the Nextcloud client on my Ubuntu notebook, changes I make to my password database are periodically pushed/pulled from my nc instance. The delay is more than noticeable.

Is this behavior platform/OS-dependent, do I need additional software for the detection of changes (pynotify etc.) or are the two clients in fact quite different? I do not see any related configuration options in the desktop client.

Similarly, the file on my Android phone is not being updated until I open the Nextcloud app (to fetch updates from the server) and manually synchronize the file (to update the local version).

Is there some way I can tell Nextcloud to keep the local file up-to-date automatically (two-way-sync)? I could not find any related configuration options either.

I’d be thankful for any pointers/best practices/advice!