Hm.The user I originally were using was also required to always enter the root password when trying to change something system relevant or so. edit: So it wasnt a root user I suppose?
I now created another user as auto log in, then the laptop screen (like no power) turned black after / while booting, I am using another screen via HDMI. Also the task bar disappeared again after logging in with the new user. OK, not my problem at the moment, whatever 
So I established a connection and configured the KDE Wallet and everything with that new user, checked if the connection is allowed to everybody (it still was). Then after autologging in the new user the above described problems appeared and the WIFI connection stated that its active, but as far as I remember the browser (FF that came with the OpenSUSE) only showed “server could not be reached” or something similiar.
Then I chose the original user to auto log in after booting and Laptop screen and task bar worked again (while second screen via HDMI attached). The mentioned system policy window is still popping up, but when I only chose cancel I can use the web browser just fine …
Strange, I am very confused now. Could be a bug and I will just have to live with canceling the window that pops up (system policy prevents modification of network settings for all users) and keep on?
Next thing i wanted to try was using something called “jamba” to comfortably exchange data between my windows PC and Linux via the LAN/WIFI and changing the swap size, the swap size by doing what you advised me to to do.
Oh well … I am so sorry for stretching your patience and would fully understand if your support stops here