I am annoyed. How hard can it be to synchronize a file between my #Nextcloud and android phone. Yes synchronize, not auto upload or download. It is supposed to always be the same. In both directions. With a copy on both sides.

The #NextcloudApp is buggy and synchronization still does not seem to be implemented (atleast I could not manage to get it to upload the file to remote after a change). And there is zero open-source apps for #webdav synchronization, if I only want to sync one folder? WTF

Is there anything I am missing?

"2-way-sync" just does not seem to do anything 2-way.
I found #EasySync from F-Droid, but that just Syncs the whole phone.
#DAVx5 does not create a local copy.
FolderSync does not seem to be OpenSource.

So, there is nothing?

@IchMeine
There is absolutely the one and only #syncthing
Once tried, there is no looking back.
@SanskritFritz
The problem is that syncthing needs the software on both sides and does not really synchronise with the nextcloud. So if I do not use my PC for a while and change the file from the smartphone, the version on nextcloud will be outdated compared to the version on my smartphone. I can also not add a new device without access to one of the devices that are currently synchronising.
I would like the file to always be current on nextcloud, with the devices interacting with that.
@IchMeine
Ah so Nextcloud is a must. Then Syncthing won't help you, I agree.