Hello @ntses.ya 
Most likely the screen ONLY supports officially the native resolution. Any lower resolution is calculated. It can work, but doesn’t have to. It’s more a trail&error method. Therefore I would suggest using scaling instead.
For more scaling steps that 100% and 200% enable the experimental feature:
Maybe check the EDID of the monitor:
pamac install base-devel
pamac build edid-decode-git
find -L /sys/class/drm/ -maxdepth 2 -type f -iname "*edid" -exec edid-decode "{}" \; 2>/dev/null