SUMMARY
I reduce the brightness to 25-35% in the DDC/CI slider of the 'Display Configuration' window. I put my PC into sleep, next day I wake it up and the brightness resets to whatever the default is which is very bright. I have to reduce it again using the 'Control hardware brightness with DDC/CI' slider. The thing is the slider position remains at a value what I had manually set it at prior to waking up but the actual brightness of the monitor resets to the default. This weird behavior persists every single time - no exceptions!

STEPS TO REPRODUCE
1.  Change the monitor brightness using the 'Control hardware brightness with DDC/CI' slider.
2.  Put the computer to Sleep/Suspend state.
3.  Wake the computer up.

OBSERVED RESULT
Brightness resets to something else.

EXPECTED RESULT
If I set it to say 30%, it should have remained at 30%. The slider position does remain at 30% but the actual brightness resets to something else (very high).

SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 42
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.18.0
Qt Version: 6.9.2
Kernel Version: 6.16.10-200.fc42.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i7-5775C CPU @ 3.30GHz
Memory: 32 GiB of RAM (31.2 GiB usable)
Graphics Processor 1: AMD Radeon RX 5700 XT
Graphics Processor 2: Intel® Iris® Pro Graphics 6200

ADDITIONAL INFORMATION
Motherboard Model: Asus Z97-A 
BIOS Version: 3503 (Release Date: 04/18/2018)

Number of monitors: 2
The issue persists with both of them.

Primary monitor: Samsung LF22T35 21.5' 1920x1080 HDMI only
Interface: HDMI port using monitor's original HDMI cable.
Connected to: MSI Gaming-X RX 5700 XT discrete GPU's HDMI port.

Secondary monitor: DELL E2223HN 21.5' 1920x1080 HDMI and VGA
Interface: HDMI port using monitor's original HDMI cable.
Connected to: Motherboard's HDMI port which is powered by Intel® Iris® Pro Graphics 6200. (I had to enable multiple monitor support using both dGPU and iGPU in the BIOS for this to work otherwise only the primary monitor using the dGPU shows up on the OS.