Sync conflict, downloading instead of uploading

Nextcloud version (eg, 12.0.2): 17.0.1
Operating system and version (eg, Ubuntu 17.04): Ubuntu Server 18.04.3
Nextcloud Client: 2.6.1 on Linux Mint 19.2

I try to backup files to a nextcloud server at my parents house.
I get sync conflicts (copy gets downloaded from the server) or data is just downloaded from the server at random, causing unnessesary disk degradation.
Maybe it is because the data folder is completely switched out by my backup mechanism (rsync with hardlinks) on a daily basis via mv command, so backup.daily.2 becomes backup.daily.3 once a day. daily.3 is the folder that is getting synced instead of the live data as a little pracaution für eventual ransomeware infection.

Somebody got an idea what is going wrong there?

In general (or if i can not get this fixed) it would be good to have an option to force the client to upload (client -> server) instead of downloading (bi-directional). I use FolderSync on Android to sync some files, and i can tell it to either go client>server, server>client or bidirectional, is this possible with the client, too? this should be an option in the client, but i didn’t find one, maybe there is something i can change in the config-file of nextcloud client?

greetings

STonE

seems like this is not gonna be answered … do i need to provide more info? if so what information?

It has been 3 months now and nobody has even the slightest hint for me what i could do?
I am not able to back up my files so this is a huge issue for me …