This is only a solution meant to maybe help someone and i didn’t find some place to put it elsewhere:
I searched for a Solution to sync my Firefox-Profile between different PCs to always have the same look and Settings and also for a Backup- Solution. I found a good way to sync it to my Nextcloud- Server, but integrating it in the client, caused troubles when running Firefox and the client trying to sync each accessed file on the fly (conflicting copys, crashes of nextcloud- client).
So i wrote a small script to sync my Profile at KDE- Logon/logoff. You can find it here:
Thats it, have fun!