I tried Manjaro with KDE Plasma and now on Kubuntu, the same problem persists. I can't control volume when using speakers, the slider and hotkeys just don't do anything, the volume is always on max. When plugging headphones it works, but strange cracking noise appears (for now it seems like gone, I'll keep watching).
Can it be due to btrfs filesystem? That's the only thing I changed since using Ubuntu for 3 years.

You need to be a tad more specific on how you connected your sound devices, what you have configured in System Settings -> Hardware -> Audio and whether you made any changes to the default sound system, namely Pulseaudio

Mamarok wrote:You need to be a tad more specific on how you connected your sound devices, what you have configured in System Settings -> Hardware -> Audio and whether you made any changes to the default sound system, namely Pulseaudio

Thank you, sure.
I'm on laptop, so I meant built-in. I didn't make any changes to Pulseaudio or Audio settings. The was only one device available to choose from and option "Analog Stereo Duplex" chosen by default. I tried Manjaro KDE, Kubuntu and now I'm on Ubuntu Budgie, and even though the latter is different desktop environment, the problem persists on all 3 of them. (so maybe I'm on the wrong forum here, by I tried others as well)

Well, all of them use Pulseaudio, so I guess you need to give your PA configuration (which is the configuration I was talking about in System Settings)
Are you talking about the built-in speakers or external ones?
Audio Volume is set by Devices, and then by Applications, you can change volume in both.

Mamarok wrote:Well, all of them use Pulseaudio, so I guess you need to give your PA configuration (which is the configuration I was talking about in System Settings)
Are you talking about the built-in speakers or external ones?
Audio Volume is set by Devices, and then by Applications, you can change volume in both.

Not much really in settings here, if these are the ones.
Yes, again, I'm on laptop and only use built-in speakers.
I can change volume per application, but system volume slider doesn't do anything, which is the problem.

Looks a tad odd TBH, but I am not used to other desktops. That is my output:
https://i.imgur.com/PN4BiHh.png
and there is also the configuration settings that look like this:
https://i.imgur.com/X2Xx2Cm.png

if you can't change the System Volume, maybe something is wrong in your Pulseaudio configuration settings? Other tools like Pavucontrol might come in helpful for this