Frequent periods of unresponsiveness for 10 to 20 seconds at least on a fresh KDE install(with some programs)

so its only 2 apps that are causing you the issue so far?
post logs from the frozen boot:
journalctl -b-1 -p4 --no-pager

Normally not. The coolbits which needs to be set (need to be written in the config file), unlocks functionalities of the driver and is not written somehow on the gpu. So it will not affect windows in any way.

I tried with avidemux-qt, handbrake and clementine now. Of those only Clementine is unresponsive and only when I try to play file.

And journalctl -b-1 -p4 --no-pager

Aug 31 12:02:59 man-jon-desk kernel:   #9 #10 #11 #12 #13 #14 #15
Aug 31 12:02:59 man-jon-desk kernel: efifb: Ignoring BGRT: unexpected or invalid BMP data
Aug 31 12:02:59 man-jon-desk kernel: nvme nvme1: missing or invalid SUBNQN field.
Aug 31 12:02:59 man-jon-desk kernel: ata1.00: supports DRM functions and may not be fully accessible
Aug 31 12:02:59 man-jon-desk kernel: ata1.00: supports DRM functions and may not be fully accessible
Aug 31 12:02:59 man-jon-desk kernel: ata2.00: supports DRM functions and may not be fully accessible
Aug 31 12:02:59 man-jon-desk kernel: ata2.00: supports DRM functions and may not be fully accessible
Aug 31 12:02:59 man-jon-desk kernel: ata6: failed to resume link (SControl 0)
Aug 31 12:02:59 man-jon-desk kernel: sd 6:0:0:0: [sdc] No Caching mode page found
Aug 31 12:02:59 man-jon-desk kernel: sd 6:0:0:0: [sdc] Assuming drive cache: write through
Aug 31 12:02:59 man-jon-desk kernel: nvidia: loading out-of-tree module taints kernel.
Aug 31 12:02:59 man-jon-desk kernel: nvidia: module license 'NVIDIA' taints kernel.
Aug 31 12:02:59 man-jon-desk kernel: Disabling lock debugging due to kernel taint
Aug 31 12:02:59 man-jon-desk kernel: 
Aug 31 12:02:59 man-jon-desk kernel: NVRM: loading NVIDIA UNIX x86_64 Kernel Module  515.65.01  Wed Jul 20 14:00:58 UTC 2022
Aug 31 12:03:00 man-jon-desk kernel: nvidia_uvm: module uses symbols from proprietary module nvidia, inheriting taint.
Aug 31 12:03:00 man-jon-desk systemd[636]: ConfigurationDirectory 'bluetooth' already exists but the mode is different. (File system: 755 ConfigurationDirectoryMode: 555)
Aug 31 12:03:02 man-jon-desk systemd[715]: xdg-user-dirs-update.service: Failed with result 'exit-code'.
Aug 31 12:03:02 man-jon-desk systemd[715]: Failed to start Update XDG user dir configuration.
Aug 31 12:03:04 man-jon-desk kernel: kauditd_printk_skb: 49 callbacks suppressed
Aug 31 12:03:13 man-jon-desk backlighthelper[946]: org.kde.powerdevil: no kernel backlight interface found
Aug 31 12:03:13 man-jon-desk pipewire[1044]: pw.context: 0x560b2667c180: no modules loaded from context.modules
Aug 31 12:03:15 man-jon-desk kernel: Bluetooth: hci0: command 0x0c52 tx timeout
Aug 31 12:03:22 man-jon-desk kernel: kauditd_printk_skb: 13 callbacks suppressed
Aug 31 12:03:23 man-jon-desk xdg-desktop-por[1011]: PipeWire roundtrip timed out waiting for events
Aug 31 12:03:23 man-jon-desk xdg-desktop-por[1011]: Failed connect to PipeWire: No node factory discovered
Aug 31 12:03:30 man-jon-desk pamac-manager[1262]: gdk_window_set_cursor: assertion 'GDK_IS_WINDOW (window)' failed
Aug 31 12:04:28 man-jon-desk org.kde.LogoutPrompt[1653]: Xlib:  extension "NV-GLX" missing on display ":0".
Aug 31 12:04:43 man-jon-desk sddm[681]: Authentication error: "Process crashed"
Aug 31 12:04:43 man-jon-desk sddm[681]: Auth: sddm-helper crashed (exit code 15)
Aug 31 12:04:43 man-jon-desk sddm[681]: Authentication error: "Process crashed"
Aug 31 12:04:43 man-jon-desk sddm[681]: Auth: sddm-helper exited with 15
Aug 31 12:04:43 man-jon-desk kglobalaccel5[847]: The X11 connection broke: I/O error (code 1)
Aug 31 12:04:46 man-jon-desk sddm[681]: Signal received: SIGTERM
Aug 31 12:04:47 man-jon-desk sddm[681]: QProcess: Destroyed while process ("/usr/lib/sddm/sddm-helper") is still running.
Aug 31 12:04:54 man-jon-desk kernel: kauditd_printk_skb: 7 callbacks suppressed
Aug 31 12:05:43 man-jon-desk systemd[749]: obex.service: Failed with result 'exit-code'.
Aug 31 12:05:43 man-jon-desk systemd[749]: xdg-document-portal.service: Failed with result 'exit-code'.
Aug 31 12:05:43 man-jon-desk systemd[749]: xdg-permission-store.service: Failed with result 'exit-code'.

Great! Then I’ll set them now.

clementine is no longer supported, so its not surprising it doesnt work properly …
and vlc works normally?
try installing librewolf-bin - a fork of firefox and see if it also freezes

I was about to provide logs from clementine’s freeze. I still have them, but if it’s not surprising, then they won’t help right?

no, they wont … if you want to try, you can use strawberry a supported fork of clementine

VLC cannot even start playing, but that seems to be an issue with audio. VlC as well as KDE cannot detect any audio devices, even though inxi -A lists 3
Playing aside it is slow as well, but that could be because of the audio errors

Librewolf freezes as well.
As does strawberry.

Should I shut down and test each one in a different boot, for clean logs? Or do we leave the logs?

I will reboot now either way, because neither mpc nor vlc did shutdown correctly and still have processes

Literally every program crash/freeze? Maybe try to disable the effects at the settings which uses your gpu via opengl.

are you dual booting with windows? if yes is fastboot disabled in bios - you may not have this option;
is fast startup disabled in windows
also open the nvidia settings and try with different settings like tripple buffer/composition pipeline - i dont know what settings you have there, so try with them one at a time …
also try booting into a non arch distro, for example linux mint and test in the live session with firefox if the freezes happen there too

Additionally to what @brahma says:

They seem to.
Two things:

  1. Coolbits, I have not found explanations I understand on how to set coolbits and to what to set them, to limit power. Can you give me somewhere I can look, or explain it, please?
  2. OpenGL: I read that, that could provide issues, and around where I could change the settings. I will have to reboot to provide a possible english screenshot of the KDE Compositor settings page, since it seems to differ from the information I found so far.

It should be in BIOS, because I already had a dual-boot setup on this pc earlier this year(without issues) I will check in BIOS and Windows.

Live-Boot: afai remember there was not any freeze while on the manjaro kde live boot.

I linked the gitlab page above and it has even a youtube video included:

I assume you mean in NVidias X Server Settings. Do I have to reboot, or is that unnecessary?

yes those settings, no need to reboot after changing them …
did you tested in the live session firefox, … etc and it all run properly?
did you reused your home folder after installing kde?
was there a system update after you installed kde? maybe the issue was introduced with it

Yes I did, and as mentioned before I installed my packages I had little problems on the installed system either. No, I did not bring over any data from old systems.

Indeed there was, when I installed packages. Though I think I installed a subset(i.e. mpc-qt) before, to test it and there were no problems.

That’s right the video.
I edited the xorg.conf(Must have not seen it in the Gitlab page before). And will reboot now.

so if there were no problems on live usb and fresh install before update, then something with the update is causing it

I think so too, and I am beginning to get more confident in that thought as well