Welcome to Manjaro!
- Please read this:
How to provide good information
and post some more information so we can see what’s really going on. Now we know the symptom of the disease, but we need some more probing to know where the origin lies… - An
inxi --admin --verbosity=7 --filter --no-host --width
would be the minimum required information… (Personally Identifiable Information like serial numbers and MAC addresses will be filtered out by the above command)
Also, please copy-paste that output in-between 3 backticks ``` at the beginning and end of the code/text. - the output to
xrandr
and the technical specifications of your monitor will be helpful as well because the information you’ve provided points to your Monitor / PC combo not being compatible for FHD.