You shouldn't run this with sudo, just as a regular user. What do you get if you run

$ gsettings get org.gnome.mutter experimental-features

?

Here's how it should work:

$ gsettings get org.gnome.mutter experimental-features
['scale-monitor-framebuffer']
$ gsettings set org.gnome.mutter experimental-features "[]"
$ gsettings get org.gnome.mutter experimental-features
@as []
$ gsettings reset org.gnome.mutter experimental-features
$ gsettings get org.gnome.mutter experimental-features
['scale-monitor-framebuffer']

So far, I've only tested in a VM, but the fractional scaling factors disappear from gnome-control-center once I disable "scale-monitor-framebuffer". But I'd think relogin is required for app scaling to actually change.