Fractional scaling not set in mutter

When I try to enable fractional scaling following the methods mentioned at https://askubuntu.com/questions/1029436/enable-fractional-scaling-for-ubuntu-18-04 and https://askubuntu.com/questions/1029436/enable-fractional-scaling-for-ubuntu-18-04 on my Dell XPS 13 7390 DE I get no options within Display Settings to use the fractional values. I've tried the xrandr and wayland options to no avail.

Steps to reproduce:

1.) modify gsettings for mutter experimental-features to set the value via:
     gsettings set org.gnome.mutter experimental-features "['scale-monitor-framebuffer']"

2. restart

3.) Open Display Settings; no fractional values exist