Ubuntu – Enable fractional scaling for Ubuntu 18.04

It might be that the gsettings you called is not the one provided by the system, but the one provided by, in my case, the conda/anaconda python distribution, which is causing the error message. Then, you can try directly calling the system's /usr/bin/gsettings instead.

Note, to check the full path to the gsettings you called, try which gsettings.

I do not have enough reputation to comment so I add a new answer (I do not understand this rule tbh).

Another workaround which worked for me was to set the scaling to different value than 200%, e.g. 175% or 150% both worked for me. It was still close to 200% which I initially wanted, but I am also ok with this. No screen tearing nor impact on the performance in comparison to what other users reported with the 0.9999x0.9999 hack and most importantly I do not see the cursor flickering anymore. Also you can comfortably set this up in the settings.

I am on X1 carbon 7th gen with Ubuntu 20.04 desktop.
Primary display: 1920x1080, scale 100%
Secondary display: 2560x1440 (built-in WQHD), scale 175%