- in a Terminal (CTRL+ALT+T) type sudo gedit /etc/profile.d/enable_wifi.sh and give your root password
- copy the following line, save and close: nmcli nm wifi on
Now it should be enabled every time you boot the system.
When you have problems with your OS you can spend hours and hours googling in forums for a working answer. Here I will publish only the working solutions for my problems so that you don't have to waste a lot of precious time if you have the questions I had.