Install SF-Mono-Powerline on LMDE 6 for zsh in linux terminal

I am trying to install SF-Mono-Powerline to change fonts for my terminal for the use of zsh. But however the installation of the fonts is succesful (checked it), but I am not able to choose the fonts in my terminal settings. Still only the default fonts are shown.

I downloaded the zip from the following website: https://github.com/Twixes/SF-Mono-Powerline/tree/master

Unziped it and copied all *.otf files to /usr/share/fonts/opentype and ~/.local/share/fonts (.otf) as well as in /usr/local/share/fonts (as .ttf)

Afterwards I entered fc-cache -f -v to update the fonts.

I checked the integrity by entering fc-list | grep SF-Mono-Powerline. The output:

/usr/share/fonts/opentype/SF-Mono-Powerline/SF-Mono-Powerline-HeavyItalic.otf: SF Mono Powerline:style=Heavy Italic/usr/local/share/fonts/SF-Mono-Powerline-SemiboldItalic.ttf: SF Mono Powerline:style=Semibold Italic/usr/local/share/fonts/SF-Mono-Powerline-MediumItalic.ttf: SF Mono Powerline:style=Medium Italic/usr/share/fonts/opentype/SF-Mono-Powerline/SF-Mono-Powerline-RegularItalic.otf: SF Mono Powerline:style=Regular Italic/usr/share/fonts/opentype/SF-Mono-Powerline/SF-Mono-Powerline-Semibold.otf: SF Mono Powerline:style=Semibold/usr/share/fonts/opentype/SF-Mono-Powerline/SF-Mono-Powerline-Bold.otf: SF Mono Powerline:style=Bold/usr/share/fonts/opentype/SF-Mono-Powerline/SF-Mono-Powerline-LightItalic.otf: SF Mono Powerline:style=Light Italic/usr/local/share/fonts/SF-Mono-Powerline-Medium.ttf: SF Mono Powerline:style=Medium/usr/local/share/fonts/SF-Mono-Powerline-Regular.ttf: SF Mono Powerline:style=Regular/usr/local/share/fonts/SF-Mono-Powerline-HeavyItalic.ttf: SF Mono Powerline:style=Heavy Italic/usr/local/share/fonts/SF-Mono-Powerline-LightItalic.ttf: SF Mono Powerline:style=Light Italic/usr/local/share/fonts/SF-Mono-Powerline-Semibold.ttf: SF Mono Powerline:style=Semibold/usr/local/share/fonts/SF-Mono-Powerline-BoldItalic.ttf: SF Mono Powerline:style=Bold Italic/usr/share/fonts/opentype/SF-Mono-Powerline/SF-Mono-Powerline-BoldItalic.otf: SF Mono Powerline:style=Bold Italic/usr/share/fonts/opentype/SF-Mono-Powerline/SF-Mono-Powerline-Heavy.otf: SF Mono Powerline:style=Heavy/usr/local/share/fonts/SF-Mono-Powerline-Light.ttf: SF Mono Powerline:style=Light/usr/share/fonts/opentype/SF-Mono-Powerline/SF-Mono-Powerline-Medium.otf: SF Mono Powerline:style=Medium/usr/share/fonts/opentype/SF-Mono-Powerline/SF-Mono-Powerline-Light.otf: SF Mono Powerline:style=Light/usr/local/share/fonts/SF-Mono-Powerline-Heavy.ttf: SF Mono Powerline:style=Heavy/usr/local/share/fonts/SF-Mono-Powerline-RegularItalic.ttf: SF Mono Powerline:style=Regular Italic/usr/share/fonts/opentype/SF-Mono-Powerline/SF-Mono-Powerline-Regular.otf: SF Mono Powerline:style=Regular/usr/share/fonts/opentype/SF-Mono-Powerline/SF-Mono-Powerline-MediumItalic.otf: SF Mono Powerline:style=Medium Italic/usr/share/fonts/opentype/SF-Mono-Powerline/SF-Mono-Powerline-SemiboldItalic.otf: SF Mono Powerline:style=Semibold Italic/usr/local/share/fonts/SF-Mono-Powerline-Bold.ttf: SF Mono Powerline:style=Bold

So the fonts are correctly installed. But when I enter my terminal -> properties -> Profile to change fonts, only the default fonts are shown. SF-Mono-Powerline is completly missing.

Any suggestions? Thx for your help :)

Update:I am able to set the desired font by entering the following command:

gsettings set org.gnome.desktop.interface monospace-font-name 'SF Mono Powerline normal 10'

To make the command universal:

gsettings set org.gnome.desktop.interface monospace-font-name 'fontname fontsize'

But still the fonts aren't shown in the properties for the terminal text.