a bit off topic but some advice.
DONT USE WAYLAND. Its not ready.
Always post your hardware. how is in connected? with what? it all matters?
The desktop is indicitive to the level at which the hardware has been completely and correctly configured.
This isnt windows or Enterprise Linux. This is Comunity Linux.
systemsettings > global scaling > can only work as well as you have configured your hardware and OS.
Follow and complete the links.
Install the wayland configurations as you go but comment out until later.
Remenber that monitors have settings too???
Use X11
What is your graphic card? Nvidia?
IF? your hardware has been completely and correctly configured.
Then you are using Nvidia graphic card, you can manage your displays using "Nvidia Xserver Settings" easily and graphical. Just open the application, go to "X Server Display Configuration". You can see your monitors here, just click on each you want to manage and then click advanced and change the resolutions parameter.
Another way is managing your screen resolutions by xorg.conf file. open the xorg.conf file and find the Section "Screen" ,under the SubSection "Display" add Modes "1024x768" "800x600". * turn display of with kwin > settings. Log out. log in. turn monitor on and set up with nvidia-settings.
Configure your system as per the Arch wiki in this order. Regardless of installed distro taking into account the differences in distros.
Some of the links below apply to all GPU Makes.
https://wiki.archlinux.org/title/GRUB/Tips_and_tricks#Setting_the_framebuffer_resolution
https://wiki.archlinux.org/title/GRUB/Tips_and_tricks#Disable_framebuffer
https://www.kernel.org/doc/html/v5.15/admin-guide/kernel-parameters.html
https://forum.manjaro.org/t/how-to-choose-the-proper-acpi-kernel-argument/1405
Blacklist and modeset nouveau
https://askubuntu.com/questions/841876/how-to-disable-nouveau-kernel-driver
HyperV and ZEN. Comment out Udev.
[ nano /usr/lib/udev/rules.d/40-vm-hotadd.rules ]
Copy to /etc/udev/rules.d ]
[ nano /usr/lib/udev/rules.d/40-vm-hotadd.rules ]
Kernel Mode Setting.
https://wiki.archlinux.org/title/NVIDIA#DRM_kernel_mode_setting
https://us.download.nvidia.com/XFree86/Linux-x86_64/510.54/README/xwayland.html
nvidia-drm.modesetting=1 is needed for wayland also.
Early Loading nVidia Modules.
For Ubuntu based add: nvidia nvidia_modeset nvidia_uvm nvidia_drm
each on a separate line in:
[ nano /etc/initramfs-tools/modules ]
[ update-initramfs -u ]
nVidia Hardware Accelerated Video.
https://wiki.archlinux.org/title/NVIDIA#Hardware_accelerated_video_decoding
https://wiki.archlinux.org/title/NVIDIA#Hardware_accelerated_video_encoding_with_NVENC
The latest driver package provides a udev rule which creates device nodes automatically, so no further action is required.
Overclocking
https://wiki.archlinux.org/title/NVIDIA/Tips_and_tricks#Overclocking_and_cooling
Static Clocks
https://wiki.archlinux.org/title/NVIDIA/Tips_and_tricks#Setting_static_2D/3D_clocks
Page Atrribute Table
https://wiki.archlinux.org/title/NVIDIA/Tips_and_tricks#Kernel_module_parameters
Performance Tweaks that may or may not help
https://wiki.debian.org/NvidiaGraphicsDrivers/Troubleshooting
Those are the basics for GPU
Below is the nVidia Driver 510 README.
Everything I've outline can be found in this README.
This is 100% applicable REGARDLESS of Distro or Distro re-packaged nVidia-Driver.
note: The default locations may and do vary from Distro to Distro but the config'ing is is 100% EXACTLY the SAME. *
https://us.download.nvidia.com/XFree86/Linux-x86_64/510.54/README/index.html
SIMPLE DESKTOP DISPLAY MANAGER
HOW TO CONFIGURE kDE_PLASMA :
SDDM
SDDM: MAKE DIRECTORY
[ sudo mkdir /etc/sddm.conf.d/ ]
SDDM : DPI [ nano /etc/sddm.conf.d/dpi.conf ]
Install config. using 94dpi or 93 dpi not 96dpi. theres a reason
SDDM : HiDPI
[ nano /etc/sddm.conf.d/hidpi.conf ]
Add config. but comment out incase of need to use later
see also:
https://wiki.archlinux.org/title/SDDM#Screen_resolution_is_too_low
https://wiki.archlinux.org/title/HiDPI#Tray_icons_with_fixed_size
https://wiki.archlinux.org/title/GRUB/Tips_and_tricks#Setting_the_framebuffer_resolution
https://wiki.archlinux.org/title/HiDPI#Fonts_outside_the_kernel_(tty)
SDDM : VIRTUAL KEYBOARD
[ nano /etc/sddm.conf.d/virtualkbd.conf ]
https://wiki.archlinux.org/title/SDDM#Enable_virtual_keyboard
Add config. but comment out incase of need to use later
SDDM : VIRTUAL KEYBOARD WAYLAND
https://invent.kde.org/plasma/kwin/-/wikis/Virtual-Keyboard https://doc.qt.io/qt-5/qtvirtualkeyboard-user-guide.html
SDDM : VIRTUAL KEYBOARD [ DISABLED ]
virual keyboard [ disabled ]
remove --purge :
" Arch-Linux = qt5-virtualkeyboard "
" Ubu-based" =
SDDM : WAYLAND
[ nano /etc/sddm.conf.d/10-wayland.conf ]
Add config. but comment out incase of need to use later
SDDM : WAYLAND / KDE_KWIN
[ nano /etc/sddm.conf.d/10-wayland.conf ]
Add config. but comment out incase of need to use later
SDDM : TTY1 INSTEAD OF TTY8
[ nano /etc/sddm.conf.d/tty.conf ]
https://wiki.archlinux.org/title/SDDM#SDDM_starts_on_tty1_instead_of_tty7
Install config. but using [ MinimumVT=8 ]
KDE - HiDPI / FRACTION SCALING
https://wiki.archlinux.org/title/GRUB/Tips_and_tricks#Setting_the_framebuffer_resolution
https://wiki.archlinux.org/title/HiDPI#Modern_HiDPI_support_(kmscon)
SDDM - HiDPI / FRACTION SCALING
Another few things can you confirm you've already configured Fractional Scaling and Wayland use in SDDM?
https://wiki.archlinux.org/title/SDDM#SDDM_starts_on_tty1_instead_of_tty7
https://wiki.archlinux.org/title/SDDM#Screen_resolution_is_too_low
XRANDR ( NON-WAYLAND)
https://wiki.archlinux.org/title/Xrandr#Adding_undetected_resolutions
HARDWARE / ACCELERATION / VULAN /
https://wiki.archlinux.org/title/Hardware_video_acceleration
KERNELMODE SETTING /EDID /RESOLUTION
https://wiki.archlinux.org/title/kernel_mode_setting#Forcing_modes_and_EDID
https://linuxhint.com/set_screen_resolution_linux_kernel_boot/
IMPORTANT !!!!
Have you read on the r/kDE sidebar the link:
OVER THERE >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
IMPORTANT !!!!
This wiki page can help you gather system information.
OVER THERE >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
YOUR INFORMATION:
Alway provide all non-sensitive information when posting a request for free community tech support.
---https://www.reddit.com/r/linux_gaming/wiki/faq#wiki_getting_system_information
Identify graphics information in Linux
To detect the graphics hardware in your system, use this command
[ $ lshw -c video ]
You can also use this command
[ $ lspci -k | grep -EA3 ‘VGA|3D|Display’ ]