Display brightness problem

So hi everyone.
I have installed ubuntu 20.04 I think on my ROG GL503VS laptop. I encountered some weird problems (Like AUX port sending no audio out, but getting sound in via microphone of my headset). Then I upgraded it to 21.04 which is my current version. In this process, some problems were fixed but I still had one problem, the brightness slider of the ubuntu itself wouldn't work.
I installed the brightness controller and it did the job. xrandr also was good and working, but they were not what I wanted (They seemed to change colours, not actual brightness).
After that, I tried to upgrade my kernel with the help of this article via terminal.
I had the 5.11 I think, now it's this:

$ uname -r
5.14.10-051410-generic

But now even the xrandr or the brightness controller won't change anything.
Also, it seems like that nearly all of the animations are kinda disabled?
I appreciate any kind of help to fix the brightness issue. If you have some other information about this kernel, thanks in advance for sharing it :)

Edit 1: The xrandr status:

$ xrandr
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080
default connected primary 1920x1080+0+0 0mm x 0mm
   1920x1080     77.00* 

Edit 2: OK, I've booted up the previous kernel:

$ uname -r
5.11.0-37-generic

The animations still are removed kinda, even on this kernel. The xrandr output is the same here also:

$ xrandr
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080
default connected primary 1920x1080+0+0 0mm x 0mm
   1920x1080     77.00* 

I just wanted to try the previous kernel to see if there is any differences, and there was nothing. In this kernel, I've tried setting the acpi_backlight=vendor and acpi_backlight=video but neither worked for me. They just made the brightness slider disappear from the ubuntu menus.
Am I doing something wrong? I don't have enough knowledge in ubuntu, so thank you for your help in advance :)

Edit 3: So I've updated the system to 21.10 now. Still, no animation, and no actual brightness control. xrandr is the same. Now the problem with the AUX port is back. If I connect a headset to my AUX port, the system recognizes that the sources have changed and will change the volume to which level it was before, and the microphone on it will work nicely and with no problem. But no sound will be played into the headset. Has anyone encountered this problem? Any solutions? Thanks in advance :)

Edit 4: I'm uninstalling ubuntu for now, and I'll use WSL for my work. I can't use it at this state. It's really a shame because I very badly wanted to use ubuntu as my main OS. I hope this kind of thing will be fixed in the near future :)